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JSON Functions And Operators
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<div class="fancy_toc">
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<span class="fancy_toc_mark" id="toc_mk">►</span>
Table Of Contents
</a>
<div id="toc_sub"><div class="fancy-toc1"><a href="#overview">1. Overview</a></div>
<div class="fancy-toc1"><a href="#compiling_in_json_support">2. Compiling in JSON Support</a></div>
<div class="fancy-toc1"><a href="#interface_overview">3. Interface Overview</a></div>
<div class="fancy-toc2"><a href="#json_arguments">3.1. JSON arguments</a></div>
<div class="fancy-toc2"><a href="#path_arguments">3.2. PATH arguments</a></div>
<div class="fancy-toc2"><a href="#value_arguments">3.3. VALUE arguments</a></div>
<div class="fancy-toc2"><a href="#compatibility">3.4. Compatibility</a></div>
<div class="fancy-toc1"><a href="#function_details">4. Function Details</a></div>
<div class="fancy-toc2"><a href="#the_json_function">4.1. The json() function</a></div>
<div class="fancy-toc2"><a href="#the_json_array_function">4.2. The json_array() function</a></div>
<div class="fancy-toc2"><a href="#the_json_array_length_function">4.3. The json_array_length() function</a></div>
<div class="fancy-toc2"><a href="#the_json_extract_function">4.4. The json_extract() function</a></div>
<div class="fancy-toc2"><a href="#the_and_operators">4.5. The -> and ->> operators</a></div>
<div class="fancy-toc2"><a href="#the_json_insert_json_replace_and_json_set_functions">4.6. The json_insert(), json_replace, and json_set() functions</a></div>
<div class="fancy-toc2"><a href="#the_json_object_function">4.7. The json_object() function</a></div>
<div class="fancy-toc2"><a href="#the_json_patch_function">4.8. The json_patch() function</a></div>
<div class="fancy-toc2"><a href="#the_json_remove_function">4.9. The json_remove() function</a></div>
<div class="fancy-toc2"><a href="#the_json_type_function">4.10. The json_type() function</a></div>
<div class="fancy-toc2"><a href="#the_json_valid_function">4.11. The json_valid() function</a></div>
<div class="fancy-toc2"><a href="#the_json_quote_function">4.12. The json_quote() function</a></div>
<div class="fancy-toc2"><a href="#the_json_group_array_and_json_group_object_aggregate_sql_functions">4.13. The json_group_array() and json_group_object()
aggregate SQL functions</a></div>
<div class="fancy-toc2"><a href="#the_json_each_and_json_tree_table_valued_functions">4.14. The json_each() and json_tree() table-valued functions</a></div>
<div class="fancy-toc3"><a href="#examples_using_json_each_and_json_tree_">4.14.1. Examples using json_each() and json_tree()</a></div>
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<h1 id="overview"><span>1. </span>Overview</h1>
<p>
By default, SQLite supports fifteen functions and two operators for
dealing with JSON values. There are also two <a href="vtab.html#tabfunc2">table-valued functions</a>
that can be used to decompose a JSON string.
</p><p>
There are 15 scalar functions and operators:
</p><ol>
<li value='1'>
<a href='#jmini'>json</a>(<i>json</i>)
</li>
<li value='2'>
<a href='#jarray'>json_array</a>(<i>value1</i>,<i>value2</i>,...)
</li>
<li value='3'>
<a href='#jarraylen'>json_array_length</a>(<i>json</i>)<br><a href='#jarraylen'>json_array_length</a>(<i>json</i>,<i>path</i>)
</li>
<li value='4'>
<a href='#jex'>json_extract</a>(<i>json</i>,<i>path</i>,...)
</li>
<li value='5'>
<i>json</i> <a href='#jptr'>-></a> <i>path</i>
</li>
<li value='6'>
<i>json</i> <a href='#jptr'>->></a> <i>path</i>
</li>
<li value='7'>
<a href='#jins'>json_insert</a>(<i>json</i>,<i>path</i>,<i>value</i>,...)
</li>
<li value='8'>
<a href='#jobj'>json_object</a>(<i>label1</i>,<i>value1</i>,...)
</li>
<li value='9'>
<a href='#jpatch'>json_patch</a>(<i>json</i>1,json2)
</li>
<li value='10'>
<a href='#jrm'>json_remove</a>(<i>json</i>,<i>path</i>,...)
</li>
<li value='11'>
<a href='#jrepl'>json_replace</a>(<i>json</i>,<i>path</i>,<i>value</i>,...)
</li>
<li value='12'>
<a href='#jset'>json_set</a>(<i>json</i>,<i>path</i>,<i>value</i>,...)
</li>
<li value='13'>
<a href='#jtype'>json_type</a>(<i>json</i>)<br><a href='#jtype'>json_type</a>(<i>json</i>,<i>path</i>)
</li>
<li value='14'>
<a href='#jvalid'>json_valid</a>(<i>json</i>)
</li>
<li value='15'>
<a href='#jquote'>json_quote</a>(<i>value</i>)
</li>
</ol>
<p>There are two aggregate SQL functions:
</p><ol>
<li value='16'>
<a href='#jgrouparray'>json_group_array</a>(<i>value</i>)
</li>
<li value='17'>
<a href='#jgroupobject'>json_group_object</a>(name,<i>value</i>)
</li>
</ol>
<p>The two <a href="vtab.html#tabfunc2">table-valued functions</a> are:
</p><ol>
<li value='18'>
<a href='#jeach'>json_each</a>(<i>json</i>)<br><a href='#jeach'>json_each</a>(<i>json</i>,<i>path</i>)
</li>
<li value='19'>
<a href='#jtree'>json_tree</a>(<i>json</i>)<br><a href='#jtree'>json_tree</a>(<i>json</i>,<i>path</i>)
</li>
</ol>
<style>
.jans {color: #050;}
.jex {color: #025;}
</style>
<a name="howtocompile"></a>
<h1 id="compiling_in_json_support"><span>2. </span>Compiling in JSON Support</h1>
<p>
The JSON functions and operators are built into SQLite by default,
as of SQLite version 3.38.0 (2022-02-22). They can be omitted
by adding the -DSQLITE_OMIT_JSON compile-time option. Prior to
version 3.38.0, the JSON functions were an extension that would only
be included in builds if the -DSQLITE_ENABLE_JSON1 compile-time option
was included. In other words, the JSON functions went from being
opt-in with SQLite version 3.37.2 and earlier to opt-out with
SQLite version 3.38.0 and later.
</p><h1 id="interface_overview"><span>3. </span>Interface Overview</h1>
<p>
SQLite stores JSON as ordinary text.
Backwards compatibility constraints mean that SQLite is only able to
store values that are NULL, integers, floating-point numbers, text,
and BLOBs. It is not possible to add a sixth "JSON" type.
</p><p>
SQLite does not (currently) support a binary encoding
of JSON. Experiments have been unable to find a binary encoding
that is significantly smaller or faster than a plain text encoding.
(The present implementation parses JSON text at over 1 GB/s.)
All JSON functions currently throw an error if any of their
arguments are BLOBs because BLOBs are reserved
for a future enhancement in which BLOBs will store the binary encoding
for JSON.
</p><h2 id="json_arguments"><span>3.1. </span>JSON arguments</h2>
<p>
For functions that accept JSON as their first argument, that argument
can be a JSON object, array, number, string, or null. SQLite numeric
values and NULL values are interpreted as JSON numbers and nulls, respectively.
SQLite text values can be understood as JSON objects, arrays, or strings.
If an SQLite text value that is not a well-formed JSON object, array, or
string is passed into JSON function, that function will usually throw
an error. (Exceptions to this rule are <a href="json1.html#jvalid">json_valid()</a> and
<a href="json1.html#jquote">json_quote()</a>.)
</p><p>
For the purposes of determining validity, leading and trailing whitespace
on JSON inputs is ignored. Interior whitespace is also ignored, in accordance
with the JSON spec. These routines accept exactly the
<a href="http://www.rfc-editor.org/rfc/rfc7159.txt">rfc-7159 JSON syntax</a>
— no more and no less.
<a name="jsonpath"></a>
</p><h2 id="path_arguments"><span>3.2. </span>PATH arguments</h2>
<p>
For functions that accept PATH arguments, that PATH must be well-formed or
else the function will throw an error.
A well-formed PATH is a text value that begins with exactly one
'$' character followed by zero or more instances
of ".<i>objectlabel</i>" or "[<i>arrayindex</i>]".
</p><p>
The <i>arrayindex</i> is usually a non-negative integer <i>N</i>. In
that case, the array element selected is the <i>N</i>-th element
of the array, starting with zero on the left.
The <i>arrayindex</i> can also be of the form "<b>#-</b><i>N</i>"
in which case the element selected is the <i>N</i>-th from the
right. The last element of the array is "<b>#-1</b>". Think of
the "#" characters as the "number of elements in the array". Then
the expression "#-1" evaluates to the integer that corresponds to
the last entry in the array. It is sometimes useful for the array
index to be just the <b>#</b> character, for example when appending
a value to an existing JSON array:
<ul>
<li><span class='jex'>json_set('[0,1,2]','$[#]','new')</span>
<span class='jans'>→ '[0,1,2,"new"]'</span></li>
</ul>
<a name="varg"></a>
</p><h2 id="value_arguments"><span>3.3. </span>VALUE arguments</h2>
<p>
For functions that accept "<i>value</i>" arguments (also shown as
"<i>value1</i>" and "<i>value2</i>"),
those arguments are usually understood
to be literal strings that are quoted and become JSON string values
in the result. Even if the input <i>value</i> strings look like
well-formed JSON, they are still interpreted as literal strings in the
result.
</p><p>
However, if a <i>value</i> argument comes directly from the result of another
JSON function or from <a href="json1.html#jptr">the -> operator</a> (but not <a href="json1.html#jptr">the ->> operator</a>),
then the argument is understood to be actual JSON and
the complete JSON is inserted rather than a quoted string.
</p><p>
For example, in the following call to json_object(), the <i>value</i>
argument looks like a well-formed JSON array. However, because it is just
ordinary SQL text, it is interpreted as a literal string and added to the
result as a quoted string:
<ul>
<li><span class='jex'>json_object('ex','[52,3.14159]')</span>
<span class='jans'>→ '{"ex":"[52,3.14159]"}'</span></li>
<li><span class='jex'>json_object('ex',('52,3.14159]'->>'$'))</span>
<span class='jans'>→ '{"ex":"[52,3.14159]"}'</span></li>
</ul>
</p><p>
But if the <i>value</i> argument in the outer json_object() call is the
result of another JSON function like <a href="json1.html#jmini">json()</a> or <a href="json1.html#jarray">json_array()</a>, then
the value is understood to be actual JSON and is inserted as such:
<ul>
<li><span class='jex'>json_object('ex',json('[52,3.14159]'))</span>
<span class='jans'>→ '{"ex":[52,3.14159]}'</span></li>
<li><span class='jex'>json_object('ex',json_array(52,3.14159))</span>
<span class='jans'>→ '{"ex":[52,3.14159]}'</span></li>
<li><span class='jex'>json_object('ex','[52,3.14159]'->'$')</span>
<span class='jans'>→ '{"ex":[52,3.14159]}'</span></li>
</ul>
</p><p>
To be clear: "<i>json</i>" arguments are always interpreted as JSON
regardless of where the value for that argument comes from. But
"<i>value</i>" arguments are only interpreted as JSON if those arguments
come directly from another JSON function or <a href="json1.html#jptr">the -> operator</a>.
</p><h2 id="compatibility"><span>3.4. </span>Compatibility</h2>
<p>
The current implementation of this JSON library uses a recursive descent
parser. In order to avoid using excess stack space, any JSON input that has
more than 2000 levels of nesting is considered invalid. Limits on nesting
depth are allowed for compatible implementations of JSON by
<a href="https://tools.ietf.org/html/rfc7159#section-9">RFC-7159 section 9</a>.
</p><h1 id="function_details"><span>4. </span>Function Details</h1>
<p>The following sections provide additional detail on the operation of
the various JSON functions and operators:
<a name="jmini"></a>
</p><h2 id="the_json_function"><span>4.1. </span>The json() function</h2>
<p>The json(X) function verifies that its argument X is a valid
JSON string and returns a minified version of that JSON string
(with all unnecessary whitespace removed). If X is not a well-formed
JSON string, then this routine throws an error.
</p><p>In other words, this function converts raw text that looks like
JSON into actual JSON so that it may be passed into the <a href="json1.html#varg">value argument</a>
of some other json function and will be interpreted as JSON rather than
a string. This function is not appropriate for testing whether or not
a particular string is well-formed JSON - use the <a href="json1.html#jvalid">json_valid()</a> routine
below for that task.
</p><p>If the argument X to json(X) contains JSON objects with duplicate
labels, then it is undefined whether or not the duplicates are
preserved. The current implementation preserves duplicates.
However, future enhancements
to this routine may choose to silently remove duplicates.
</p><p>
Example:
<ul>
<li><span class='jex'>json(' { "this" : "is", "a": [ "test" ] } ')</span>
<span class='jans'>→ '{"this":"is","a":["test"]}'</span></li>
</ul>
<a name="jarray"></a>
</p><h2 id="the_json_array_function"><span>4.2. </span>The json_array() function</h2>
<p>The json_array() SQL function accepts zero or more arguments and
returns a well-formed JSON array that is composed from those arguments.
If any argument to json_array() is a BLOB then an error is thrown.
</p><p>An argument with SQL type TEXT is normally converted into a quoted
JSON string. However, if the argument is the output from another json1
function, then it is stored as JSON. This allows calls to json_array()
and <a href="json1.html#jobj">json_object()</a> to be nested. The <a href="json1.html#jmini">json()</a> function can also
be used to force strings to be recognized as JSON.
</p><p>Examples:
<ul>
<li><span class='jex'>json_array(1,2,'3',4)</span>
<span class='jans'>→ '[1,2,"3",4]'</span></li>
<li><span class='jex'>json_array('[1,2]')</span>
<span class='jans'>→ '["[1,2]"]'</span></li>
<li><span class='jex'>json_array(json_array(1,2))</span>
<span class='jans'>→ '[[1,2]]'</span></li>
<li><span class='jex'>json_array(1,null,'3','[4,5]','{"six":7.7}')</span>
<span class='jans'>→ '[1,null,"3","[4,5]","{\"six\":7.7}"]'</span></li>
<li><span class='jex'>json_array(1,null,'3',json('[4,5]'),json('{"six":7.7}'))</span>
<span class='jans'>→ '[1,null,"3",[4,5],{"six":7.7}]'</span></li>
</ul>
<a name="jarraylen"></a>
</p><h2 id="the_json_array_length_function"><span>4.3. </span>The json_array_length() function</h2>
<p>The json_array_length(X) function returns the number of elements
in the JSON array X, or 0 if X is some kind of JSON value other
than an array. The json_array_length(X,P) locates the array at path P
within X and returns the length of that array, or 0 if path P locates
an element or X other than a JSON array, and NULL if path P does not
locate any element of X. Errors are thrown if either X is not
well-formed JSON or if P is not a well-formed path.
</p><p>Examples:
<ul>
<li><span class='jex'>json_array_length('[1,2,3,4]')</span>
<span class='jans'>→ 4</span></li>
<li><span class='jex'>json_array_length('[1,2,3,4]', '$')</span>
<span class='jans'>→ 4</span></li>
<li><span class='jex'>json_array_length('[1,2,3,4]', '$[2]')</span>
<span class='jans'>→ 0</span></li>
<li><span class='jex'>json_array_length('{"one":[1,2,3]}')</span>
<span class='jans'>→ 0</span></li>
<li><span class='jex'>json_array_length('{"one":[1,2,3]}', '$.one')</span>
<span class='jans'>→ 3</span></li>
<li><span class='jex'>json_array_length('{"one":[1,2,3]}', '$.two')</span>
<span class='jans'>→ NULL</span></li>
</ul>
<a name="jex"></a>
</p><h2 id="the_json_extract_function"><span>4.4. </span>The json_extract() function</h2>
<p>The json_extract(X,P1,P2,...) extracts and returns one or more
values from the
well-formed JSON at X. If only a single path P1 is provided, then the
SQL datatype of the result is NULL for a JSON null, INTEGER or REAL
for a JSON numeric value, an INTEGER zero for a JSON false value,
an INTEGER one for a JSON true value, the dequoted text for a
JSON string value, and a text representation for JSON object and array values.
If there are multiple path arguments (P1, P2, and so forth) then this
routine returns SQLite text which is a well-formed JSON array holding
the various values.
</p><p>Examples:
<ul>
<li><span class='jex'>json_extract('{"a":2,"c":[4,5,{"f":7}]}', '$')</span>
<span class='jans'>→ '{"a":2,"c":[4,5,{"f":7}]}'</span></li>
<li><span class='jex'>json_extract('{"a":2,"c":[4,5,{"f":7}]}', '$.c')</span>
<span class='jans'>→ '[4,5,{"f":7}]'</span></li>
<li><span class='jex'>json_extract('{"a":2,"c":[4,5,{"f":7}]}', '$.c[2]')</span>
<span class='jans'>→ '{"f":7}'</span></li>
<li><span class='jex'>json_extract('{"a":2,"c":[4,5,{"f":7}]}', '$.c[2].f')</span>
<span class='jans'>→ 7</span></li>
<li><span class='jex'>json_extract('{"a":2,"c":[4,5],"f":7}','$.c','$.a')</span>
<span class='jans'>→ '[[4,5],2]'</span></li>
<li><span class='jex'>json_extract('{"a":2,"c":[4,5],"f":7}','$.c[#-1]')</span>
<span class='jans'>→ 5</span></li>
<li><span class='jex'>json_extract('{"a":2,"c":[4,5,{"f":7}]}', '$.x')</span>
<span class='jans'>→ NULL</span></li>
<li><span class='jex'>json_extract('{"a":2,"c":[4,5,{"f":7}]}', '$.x', '$.a')</span>
<span class='jans'>→ '[null,2]'</span></li>
<li><span class='jex'>json_extract('{"a":"xyz"}', '$.a')</span>
<span class='jans'>→ 'xyz'</span></li>
<li><span class='jex'>json_extract('{"a":null}', '$.a')</span>
<span class='jans'>→ NULL</span></li>
</ul>
</p><p>There is a subtle incompatibility between the json_extract() function
in SQLite and the json_extract() function in MySQL. The MySQL version
of json_extract() always returns JSON. The SQLite version of
json_extract() only returns JSON if there are two or more PATH arguments
(because the result is then a JSON array) or if the single PATH argument
references an array or object. In SQLite, if json_extract() has only
a single PATH argument and that PATH references a JSON null or a string
or a numeric value, then json_extract() returns the corresponding SQL
NULL, TEXT, INTEGER, or REAL value.
</p><p>The difference between MySQL json_extract() and SQLite json_extract()
really only stands out when accessing individual values within the JSON
that are strings or NULLs. The following table demonstrates the difference:
</p><center>
<table border="1" cellpadding="3" cellspacing="0">
<tr><th>Operation</th><th>SQLite Result</th><th>MySQL Result
</th></tr><tr><td>json_extract('{"a":null,"b":"xyz"}','$.a')</td><td>NULL</td><td>'null'
</td></tr><tr><td>json_extract('{"a":null,"b":"xyz"}','$.b')</td><td>'xyz'</td><td>'"xyz"'
</td></tr></table></center>
<a name="jptr"></a>
<h2 id="the_and_operators"><span>4.5. </span>The -> and ->> operators</h2>
<p>Beginning with SQLite version 3.38.0 (2022-02-22), the ->
and ->> operators are available for extracting subcomponents of JSON.
The SQLite implementation of the -> and ->> operators strive to be
compatible with both MySQL and PostgreSQL.
The -> and ->> operators take a JSON string
as their left operand and a PATH expression or object field
label or array index as their right operand. The -> operator
returns a JSON representation of the selected subcomponent or NULL if that
subcomponent does not exist. The ->> operator returns an SQL TEXT,
INTEGER, REAL, or NULL value that represents the selected subcomponent,
or NULL if the subcomponent does not exist.
</p><p>Both the -> and ->> operators select the same subcomponent
of the JSON to their left. The difference is that -> always returns a
JSON representation of that subcomponent and the ->> operator always
returns an SQL representation of that subcomponent. Thus, these operators
are subtly different from a two-argument <a href="json1.html#jex">json_extract()</a> function call.
A call to json_extract() with two arguments will return a JSON representation
of the subcomponent if and only if the subcomponent is a JSON array or
object, and will return an SQL representation of the subcomponent if the
subcomponent is a JSON null, string, or numeric value.
</p><p>The right-hand operand to the -> and ->> operators can
be a well-formed JSON path expression. This is the form used by MySQL.
For compatibility with PostgreSQL,
the -> and ->> operators also accept a text label or
integer as their right-hand operand. If the right operand is a text
label X, then it is interpreted as the JSON path '$.X'. If the right
operand is an integer value N, then it is interpreted as the JSON path '$[N]'.
</p><p>Examples:
<ul>
<li><span class='jex'>'{"a":2,"c":[4,5,{"f":7}]}' -> '$'</span>
<span class='jans'>→ '{"a":2,"c":[4,5,{"f":7}]}'</span></li>
<li><span class='jex'>'{"a":2,"c":[4,5,{"f":7}]}' -> '$.c'</span>
<span class='jans'>→ '[4,5,{"f":7}]'</span></li>
<li><span class='jex'>'{"a":2,"c":[4,5,{"f":7}]}' -> 'c'</span>
<span class='jans'>→ '[4,5,{"f":7}]'</span></li>
<li><span class='jex'>'{"a":2,"c":[4,5,{"f":7}]}' -> '$.c[2]'</span>
<span class='jans'>→ '{"f":7}'</span></li>
<li><span class='jex'>'{"a":2,"c":[4,5,{"f":7}]}' -> '$.c[2].f'</span>
<span class='jans'>→ '7'</span></li>
<li><span class='jex'>'{"a":2,"c":[4,5],"f":7}' -> '$.c[#-1]'</span>
<span class='jans'>→ '5'</span></li>
<li><span class='jex'>'{"a":2,"c":[4,5,{"f":7}]}' -> '$.x'</span>
<span class='jans'>→ NULL</span></li>
<li><span class='jex'>'[11,22,33,44]' -> 3</span>
<span class='jans'>→ '44'</span></li>
<li><span class='jex'>'[11,22,33,44]' ->> 3</span>
<span class='jans'>→ 44</span></li>
<li><span class='jex'>'{"a":"xyz"}' -> '$.a'</span>
<span class='jans'>→ '"xyz"'</span></li>
<li><span class='jex'>'{"a":"xyz"}' ->> '$.a'</span>
<span class='jans'>→ 'xyz'</span></li>
<li><span class='jex'>'{"a":null}' -> '$.a'</span>
<span class='jans'>→ 'null'</span></li>
<li><span class='jex'>'{"a":null}' ->> '$.a'</span>
<span class='jans'>→ NULL</span></li>
</ul>
<a name="jins"></a>
<a name="jrepl"></a>
<a name="jset"></a>
</p><h2 id="the_json_insert_json_replace_and_json_set_functions"><span>4.6. </span>The json_insert(), json_replace, and json_set() functions</h2>
<p>The json_insert(), json_replace, and json_set() functions all take
a single JSON value as their first argument followed by zero or more
pairs of path and value arguments, and return a new JSON string formed
by updating the input JSON by the path/value pairs. The functions
differ only in how they deal with creating new values and overwriting
preexisting values.
</p><center>
<table border="1" cellpadding="3" cellspacing="0">
<tr>
<th>Function</th><th>Overwrite if already exists?</th><th>Create if does not exist?
</th></tr><tr>
<td>json_insert()</td><td align="center">No</td><td align="center">Yes
</td></tr><tr>
<td>json_replace()</td><td align="center">Yes</td><td align="center">No
</td></tr><tr>
<td>json_set()</td><td align="center">Yes</td><td align="center">Yes
</td></tr></table></center>
<p>The json_insert(), json_replace(), and json_set() functions always
take an odd number of arguments. The first argument is always the original
JSON to be edited. Subsequent arguments occur in pairs with the first
element of each pair being a path and the second element being the value
to insert or replace or set on that path.
</p><p>Edits occur sequentially from left to right. Changes caused by
prior edits can affect the path search for subsequent edits.
</p><p>If the value of a path/value pair is an SQLite TEXT value, then it
is normally inserted as a quoted JSON string, even if the string looks
like valid JSON. However, if the value is the result of another
json1 function (such as <a href="json1.html#jmini">json()</a> or <a href="json1.html#jarray">json_array()</a> or <a href="json1.html#jobj">json_object()</a>)
or if it is the result of <a href="json1.html#jptr">the -> operator</a>,
then it is interpreted as JSON and is inserted as JSON retaining all
of its substructure. Values that are the result of <a href="json1.html#jptr">the ->> operator</a>
are always interpreted as TEXT and are inserted as a JSON string even
if they look like valid JSON.
</p><p>These routines throw an error if the first JSON argument is not
well-formed or if any PATH argument is not well-formed or if any
argument is a BLOB.
</p><p>To append an element onto the end of an array, using json_insert()
with an array index of "#". Examples:
<ul>
<li><span class='jex'>json_insert('[1,2,3,4]','$[#]',99)</span>
<span class='jans'>→ '[1,2,3,4,99]'</span></li>
<li><span class='jex'>json_insert('[1,[2,3],4]','$[1][#]',99)</span>
<span class='jans'>→ '[1,[2,3,99],4]'</span></li>
</ul>
</p><p>Other examples:
<ul>
<li><span class='jex'>json_insert('{"a":2,"c":4}', '$.a', 99)</span>
<span class='jans'>→ '{"a":2,"c":4}'</span></li>
<li><span class='jex'>json_insert('{"a":2,"c":4}', '$.e', 99)</span>
<span class='jans'>→ '{"a":2,"c":4,"e":99}'</span></li>
<li><span class='jex'>json_replace('{"a":2,"c":4}', '$.a', 99)</span>
<span class='jans'>→ '{"a":99,"c":4}'</span></li>
<li><span class='jex'>json_replace('{"a":2,"c":4}', '$.e', 99)</span>
<span class='jans'>→ '{"a":2,"c":4}'</span></li>
<li><span class='jex'>json_set('{"a":2,"c":4}', '$.a', 99)</span>
<span class='jans'>→ '{"a":99,"c":4}'</span></li>
<li><span class='jex'>json_set('{"a":2,"c":4}', '$.e', 99)</span>
<span class='jans'>→ '{"a":2,"c":4,"e":99}'</span></li>
<li><span class='jex'>json_set('{"a":2,"c":4}', '$.c', '[97,96]')</span>
<span class='jans'>→ '{"a":2,"c":"[97,96]"}'</span></li>
<li><span class='jex'>json_set('{"a":2,"c":4}', '$.c', json('[97,96]'))</span>
<span class='jans'>→ '{"a":2,"c":[97,96]}'</span></li>
<li><span class='jex'>json_set('{"a":2,"c":4}', '$.c', json_array(97,96))</span>
<span class='jans'>→ '{"a":2,"c":[97,96]}'</span></li>
</ul>
<a name="jobj"></a>
</p><h2 id="the_json_object_function"><span>4.7. </span>The json_object() function</h2>
<p>The json_object() SQL function accepts zero or more pairs of arguments
and returns a well-formed JSON object that is composed from those arguments.
The first argument of each pair is the label and the second argument of
each pair is the value.
If any argument to json_object() is a BLOB then an error is thrown.
</p><p>The json_object() function currently allows duplicate labels without
complaint, though this might change in a future enhancement.
</p><p>An argument with SQL type TEXT it is normally converted into a quoted
JSON string even if the input text is well-formed JSON.
However, if the argument is the direct result from another JSON
function or <a href="json1.html#jptr">the -> operator</a> (but not <a href="json1.html#jptr">the ->> operator</a>),
then it is treated as JSON and all of its JSON type information
and substructure is preserved. This allows calls to json_object()
and <a href="json1.html#jarray">json_array()</a> to be nested. The <a href="json1.html#jmini">json()</a> function can also
be used to force strings to be recognized as JSON.
</p><p>Examples:
<ul>
<li><span class='jex'>json_object('a',2,'c',4)</span>
<span class='jans'>→ '{"a":2,"c":4}'</span></li>
<li><span class='jex'>json_object('a',2,'c','{e:5}')</span>
<span class='jans'>→ '{"a":2,"c":"{e:5}"}'</span></li>
<li><span class='jex'>json_object('a',2,'c',json_object('e',5))</span>
<span class='jans'>→ '{"a":2,"c":{"e":5}}'</span></li>
</ul>
<a name="jpatch"></a>
</p><h2 id="the_json_patch_function"><span>4.8. </span>The json_patch() function</h2>
<p>The json_patch(T,P) SQL function runs the
<a href="https://tools.ietf.org/html/rfc7396">RFC-7396</a> MergePatch algorithm
to apply patch P against input T. The patched copy of T is returned.
</p><p>MergePatch can add, modify, or delete elements of a JSON Object,
and so for JSON Objects, the json_patch() routine is a generalized
replacement for <a href="json1.html#jset">json_set()</a> and <a href="json1.html#jrm">json_remove()</a>. However, MergePatch
treats JSON Array objects as atomic. MergePatch cannot append to an
Array nor modify individual elements of an Array. It can only insert,
replace, or delete the whole Array as a single unit. Hence, json_patch()
is not as useful when dealing with JSON that includes Arrays,
especially Arrays with lots of substructure.
</p><p>Examples:
<ul>
<li><span class='jex'>json_patch('{"a":1,"b":2}','{"c":3,"d":4}')</span>
<span class='jans'>→ '{"a":1,"b":2,"c":3,"d":4}'</span></li>
<li><span class='jex'>json_patch('{"a":[1,2],"b":2}','{"a":9}')</span>
<span class='jans'>→ '{"a":9,"b":2}'</span></li>
<li><span class='jex'>json_patch('{"a":[1,2],"b":2}','{"a":null}')</span>
<span class='jans'>→ '{"b":2}'</span></li>
<li><span class='jex'>json_patch('{"a":1,"b":2}','{"a":9,"b":null,"c":8}')</span>
<span class='jans'>→ '{"a":9,"c":8}'</span></li>
<li><span class='jex'>json_patch('{"a":{"x":1,"y":2},"b":3}','{"a":{"y":9},"c":8}')</span>
<span class='jans'>→ '{"a":{"x":1,"y":9},"b":3,"c":8}'</span></li>
</ul>
<a name="jrm"></a>
</p><h2 id="the_json_remove_function"><span>4.9. </span>The json_remove() function</h2>
<p>The json_remove(X,P,...) function takes a single JSON value as its
first argument followed by zero or more path arguments.
The json_remove(X,P,...) function returns
a copy of the X parameter with all the elements
identified by path arguments removed. Paths that select elements
not found in X are silently ignored.
</p><p>Removals occurs sequentially from left to right. Changes caused by
prior removals can affect the path search for subsequent arguments.
</p><p>If the json_remove(X) function is called with no path arguments,
then it returns the input X reformatted, with excess whitespace
removed.
</p><p>The json_remove() function throws an error if the first argument
is not well-formed JSON or if any later argument is not a well-formed
path, or if any argument is a BLOB.
</p><p>Examples:
<ul>
<li><span class='jex'>json_remove('[0,1,2,3,4]','$[2]')</span>
<span class='jans'>→ '[0,1,3,4]'</span></li>
<li><span class='jex'>json_remove('[0,1,2,3,4]','$[2]','$[0]')</span>
<span class='jans'>→ '[1,3,4]'</span></li>
<li><span class='jex'>json_remove('[0,1,2,3,4]','$[0]','$[2]')</span>
<span class='jans'>→ '[1,2,4]'</span></li>
<li><span class='jex'>json_remove('[0,1,2,3,4]','$[#-1]','$[0]')</span>
<span class='jans'>→ '[1,2,3]'</span></li>
<li><span class='jex'>json_remove('{"x":25,"y":42}')</span>
<span class='jans'>→ '{"x":25,"y":42}'</span></li>
<li><span class='jex'>json_remove('{"x":25,"y":42}','$.z')</span>
<span class='jans'>→ '{"x":25,"y":42}'</span></li>
<li><span class='jex'>json_remove('{"x":25,"y":42}','$.y')</span>
<span class='jans'>→ '{"x":25}'</span></li>
<li><span class='jex'>json_remove('{"x":25,"y":42}','$')</span>
<span class='jans'>→ NULL</span></li>
</ul>
<a name="jtype"></a>
</p><h2 id="the_json_type_function"><span>4.10. </span>The json_type() function</h2>
<p>The json_type(X) function returns the "type" of the outermost element
of X. The json_type(X,P) function returns the "type" of the element
in X that is selected by path P. The "type" returned by json_type() is
one of the following SQL text values:
'null', 'true', 'false', 'integer', 'real', 'text', 'array', or 'object'.
If the path P in json_type(X,P) selects an element that does not exist
in X, then this function returns NULL.
</p><p>The json_type() function throws an error if any of its arguments is
not well-formed or is a BLOB.
</p><p>Examples:
<ul>
<li><span class='jex'>json_type('{"a":[2,3.5,true,false,null,"x"]}')</span>
<span class='jans'>→ 'object'</span></li>
<li><span class='jex'>json_type('{"a":[2,3.5,true,false,null,"x"]}','$')</span>
<span class='jans'>→ 'object'</span></li>
<li><span class='jex'>json_type('{"a":[2,3.5,true,false,null,"x"]}','$.a')</span>
<span class='jans'>→ 'array'</span></li>
<li><span class='jex'>json_type('{"a":[2,3.5,true,false,null,"x"]}','$.a[0]')</span>
<span class='jans'>→ 'integer'</span></li>
<li><span class='jex'>json_type('{"a":[2,3.5,true,false,null,"x"]}','$.a[1]')</span>
<span class='jans'>→ 'real'</span></li>
<li><span class='jex'>json_type('{"a":[2,3.5,true,false,null,"x"]}','$.a[2]')</span>
<span class='jans'>→ 'true'</span></li>
<li><span class='jex'>json_type('{"a":[2,3.5,true,false,null,"x"]}','$.a[3]')</span>
<span class='jans'>→ 'false'</span></li>
<li><span class='jex'>json_type('{"a":[2,3.5,true,false,null,"x"]}','$.a[4]')</span>
<span class='jans'>→ 'null'</span></li>
<li><span class='jex'>json_type('{"a":[2,3.5,true,false,null,"x"]}','$.a[5]')</span>
<span class='jans'>→ 'text'</span></li>
<li><span class='jex'>json_type('{"a":[2,3.5,true,false,null,"x"]}','$.a[6]')</span>
<span class='jans'>→ NULL</span></li>
</ul>
<a name="jvalid"></a>
</p><h2 id="the_json_valid_function"><span>4.11. </span>The json_valid() function</h2>
<p>The json_valid(X) function return 1 if the argument X is well-formed
JSON and return 0 if the argument X is not well-formed JSON.
</p><p>Examples:
<ul>
<li><span class='jex'>json_valid('{"x":35}')</span>
<span class='jans'>→ 1</span></li>
<li><span class='jex'>json_valid('{"x":35')</span>
<span class='jans'>→ 0</span></li>
</ul>
<a name="jquote"></a>
</p><h2 id="the_json_quote_function"><span>4.12. </span>The json_quote() function</h2>
<p>The json_quote(X) function converts the SQL value X (a number or a
string) into its corresponding JSON representation. If X is a JSON value
returned by another JSON function, then this function is a no-op.
</p><p>Examples:
<ul>
<li><span class='jex'>json_quote(3.14159)</span>
<span class='jans'>→ 3.14159</span></li>
<li><span class='jex'>json_quote('verdant')</span>
<span class='jans'>→ '"verdant"'</span></li>
<li><span class='jex'>json_quote('[1]')</span>
<span class='jans'>→ '"[1]"'</span></li>
<li><span class='jex'>json_quote(json('[1]'))</span>
<span class='jans'>→ '[1]'</span></li>
<li><span class='jex'>json_quote('[1,')</span>
<span class='jans'>→ '"[1"'</span></li>
</ul>
<a name="jgrouparray"></a>
<a name="jgroupobject"></a>
</p><h2 id="the_json_group_array_and_json_group_object_aggregate_sql_functions"><span>4.13. </span>The json_group_array() and json_group_object()
aggregate SQL functions</h2>
<p>The json_group_array(X) function is an
<a href="lang_aggfunc.html">aggregate SQL function</a> that returns a JSON array
comprised of all X values in the aggregation.
Similarly, the json_group_object(NAME,VALUE) function returns a JSON object
comprised of all NAME/VALUE pairs in the aggregation.
<a name="jeach"></a>
<a name="jtree"></a>
</p><h2 id="the_json_each_and_json_tree_table_valued_functions"><span>4.14. </span>The json_each() and json_tree() table-valued functions</h2>
<p>The json_each(X) and json_tree(X) <a href="vtab.html#tabfunc2">table-valued functions</a> walk the
JSON value provided as their first argument and return one row for each
element. The json_each(X) function only walks the immediate children
of the top-level array or object,
or just the top-level element itself if the top-level
element is a primitive value.
The json_tree(X) function recursively walks through the
JSON substructure starting with the top-level element.
</p><p>The json_each(X,P) and json_tree(X,P) functions work just like
their one-argument counterparts except that they treat the element
identified by path P as the top-level element.
</p><p>The schema for the table returned by json_each() and json_tree() is
as follows:
</p><blockquote><pre>
CREATE TABLE json_tree(
key ANY, -- key for current element relative to its parent
value ANY, -- value for the current element
type TEXT, -- 'object','array','string','integer', etc.
atom ANY, -- value for primitive types, null for array & object
id INTEGER, -- integer ID for this element
parent INTEGER, -- integer ID for the parent of this element
fullkey TEXT, -- full path describing the current element
path TEXT, -- path to the container of the current row
json JSON HIDDEN, -- 1st input parameter: the raw JSON
root TEXT HIDDEN -- 2nd input parameter: the PATH at which to start
);
</pre></blockquote>
<p>
The "key" column is the integer array index for elements of a JSON array
and the text label for elements of a JSON object. The key column is
NULL in all other cases.
</p><p>
The "atom" column is the SQL value corresponding to primitive elements -
elements other than JSON arrays and objects. The "atom" column is NULL
for a JSON array or object. The "value" column is the same as the
"atom" column for primitive JSON elements but takes on the text JSON value
for arrays and objects.
</p><p>
The "type" column is an SQL text value taken from ('null', 'true', 'false',
'integer', 'real', 'text', 'array', 'object') according to the type of
the current JSON element.
</p><p>
The "id" column is an integer that identifies a specific JSON element
within the complete JSON string. The "id" integer is an internal housekeeping
number, the computation of which might change in future releases. The
only guarantee is that the "id" column will be different for every row.
</p><p>
The "parent" column is always NULL for json_each().
For json_tree(),
the "parent" column is the "id" integer for the parent of the current
element, or NULL for the top-level JSON element or the element identified
by the root path in the second argument.
</p><p>
The "fullkey" column is a text path that uniquely identifies the current
row element within the original JSON string. The complete key to the
true top-level element is returned even if an alternative starting point
is provided by the "root" argument.
</p><p>
The "path" column is the path to the array or object container that holds
the current row, or the path to the current row in the case where the
iteration starts on a primitive type and thus only provides a single
row of output.
</p><h3 id="examples_using_json_each_and_json_tree_"><span>4.14.1. </span>Examples using json_each() and json_tree()</h3>
<p>Suppose the table "CREATE TABLE user(name,phone)" stores zero or
more phone numbers as a JSON array object in the user.phone field.
To find all users who have any phone number with a 704 area code:
</p><blockquote><pre>
SELECT DISTINCT user.name
FROM user, json_each(user.phone)
WHERE json_each.value LIKE '704-%';
</pre></blockquote>
<p>Now suppose the user.phone field contains plain text if the user
has only a single phone number and a JSON array if the user has multiple
phone numbers. The same question is posed: "Which users have a phone number
in the 704 area code?" But now the json_each() function can only be called
for those users that have two or more phone numbers since json_each()
requires well-formed JSON as its first argument:
</p><blockquote><pre>
SELECT name FROM user WHERE phone LIKE '704-%'
UNION
SELECT user.name
FROM user, json_each(user.phone)
WHERE json_valid(user.phone)
AND json_each.value LIKE '704-%';
</pre></blockquote>
<p>Consider a different database with "CREATE TABLE big(json JSON)".
To see a complete line-by-line decomposition of the data:
</p><blockquote><pre>
SELECT big.rowid, fullkey, value
FROM big, json_tree(big.json)
WHERE json_tree.type NOT IN ('object','array');
</pre></blockquote>
<p>In the previous, the "type NOT IN ('object','array')" term of the
WHERE clause suppresses containers and only lets through leaf elements.
The same effect could be achieved this way:
</p><blockquote><pre>
SELECT big.rowid, fullkey, atom
FROM big, json_tree(big.json)
WHERE atom IS NOT NULL;
</pre></blockquote>
<p>Suppose each entry in the BIG table is a JSON object
with a '$.id' field that is a unique identifier
and a '$.partlist' field that can be a deeply nested object.
You want to find the id of every entry that contains one
or more references to uuid '6fa5181e-5721-11e5-a04e-57f3d7b32808' anywhere
in its '$.partlist'.
</p><blockquote><pre>
SELECT DISTINCT json_extract(big.json,'$.id')
FROM big, json_tree(big.json, '$.partlist')
WHERE json_tree.key='uuid'
AND json_tree.value='6fa5181e-5721-11e5-a04e-57f3d7b32808';
</pre></blockquote>
<p align="center"><small><i>This page last modified on <a href="https://sqlite.org/docsrc/honeypot" id="mtimelink" data-href="https://sqlite.org/docsrc/finfo/pages/json1.in?m=a3a94372544eb4e69">2022-06-24 16:56:23</a> UTC </small></i></p>
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