diff options
Diffstat (limited to 'sqlglot/expressions.py')
| -rw-r--r-- | sqlglot/expressions.py | 107 |
1 files changed, 76 insertions, 31 deletions
diff --git a/sqlglot/expressions.py b/sqlglot/expressions.py index 6bb083a..6800cd5 100644 --- a/sqlglot/expressions.py +++ b/sqlglot/expressions.py @@ -6,6 +6,7 @@ Every AST node in SQLGlot is represented by a subclass of `Expression`. This module contains the implementation of all supported `Expression` types. Additionally, it exposes a number of helper functions, which are mainly used to programmatically build SQL expressions, such as `sqlglot.expressions.select`. + ---- """ @@ -137,6 +138,8 @@ class Expression(metaclass=_Expression): return field if isinstance(field, (Identifier, Literal, Var)): return field.this + if isinstance(field, (Star, Null)): + return field.name return "" @property @@ -176,13 +179,11 @@ class Expression(metaclass=_Expression): return self.text("alias") @property - def name(self): + def name(self) -> str: return self.text("this") @property def alias_or_name(self): - if isinstance(self, Null): - return "NULL" return self.alias or self.name @property @@ -589,12 +590,11 @@ class Expression(metaclass=_Expression): return load(obj) -if t.TYPE_CHECKING: - IntoType = t.Union[ - str, - t.Type[Expression], - t.Collection[t.Union[str, t.Type[Expression]]], - ] +IntoType = t.Union[ + str, + t.Type[Expression], + t.Collection[t.Union[str, t.Type[Expression]]], +] class Condition(Expression): @@ -939,7 +939,7 @@ class EncodeColumnConstraint(ColumnConstraintKind): class GeneratedAsIdentityColumnConstraint(ColumnConstraintKind): # this: True -> ALWAYS, this: False -> BY DEFAULT - arg_types = {"this": True, "start": False, "increment": False} + arg_types = {"this": False, "start": False, "increment": False} class NotNullColumnConstraint(ColumnConstraintKind): @@ -2390,7 +2390,7 @@ class Star(Expression): arg_types = {"except": False, "replace": False} @property - def name(self): + def name(self) -> str: return "*" @property @@ -2413,6 +2413,10 @@ class Placeholder(Expression): class Null(Condition): arg_types: t.Dict[str, t.Any] = {} + @property + def name(self) -> str: + return "NULL" + class Boolean(Condition): pass @@ -2644,7 +2648,9 @@ class Div(Binary): class Dot(Binary): - pass + @property + def name(self) -> str: + return self.expression.name class DPipe(Binary): @@ -2961,7 +2967,7 @@ class Cast(Func): arg_types = {"this": True, "to": True} @property - def name(self): + def name(self) -> str: return self.this.name @property @@ -4027,17 +4033,39 @@ def paren(expression) -> Paren: SAFE_IDENTIFIER_RE = re.compile(r"^[_a-zA-Z][\w]*$") -def to_identifier(alias, quoted=None) -> t.Optional[Identifier]: - if alias is None: +@t.overload +def to_identifier(name: None, quoted: t.Optional[bool] = None) -> None: + ... + + +@t.overload +def to_identifier(name: str | Identifier, quoted: t.Optional[bool] = None) -> Identifier: + ... + + +def to_identifier(name, quoted=None): + """Builds an identifier. + + Args: + name: The name to turn into an identifier. + quoted: Whether or not force quote the identifier. + + Returns: + The identifier ast node. + """ + + if name is None: return None - if isinstance(alias, Identifier): - identifier = alias - elif isinstance(alias, str): - if quoted is None: - quoted = not re.match(SAFE_IDENTIFIER_RE, alias) - identifier = Identifier(this=alias, quoted=quoted) + + if isinstance(name, Identifier): + identifier = name + elif isinstance(name, str): + identifier = Identifier( + this=name, + quoted=not re.match(SAFE_IDENTIFIER_RE, name) if quoted is None else quoted, + ) else: - raise ValueError(f"Alias needs to be a string or an Identifier, got: {alias.__class__}") + raise ValueError(f"Name needs to be a string or an Identifier, got: {name.__class__}") return identifier @@ -4112,20 +4140,31 @@ def to_column(sql_path: str | Column, **kwargs) -> Column: return Column(this=column_name, table=table_name, **kwargs) -def alias_(expression, alias, table=False, dialect=None, quoted=None, **opts): - """ - Create an Alias expression. +def alias_( + expression: str | Expression, + alias: str | Identifier, + table: bool | t.Sequence[str | Identifier] = False, + quoted: t.Optional[bool] = None, + dialect: DialectType = None, + **opts, +): + """Create an Alias expression. + Example: >>> alias_('foo', 'bar').sql() 'foo AS bar' + >>> alias_('(select 1, 2)', 'bar', table=['a', 'b']).sql() + '(SELECT 1, 2) AS bar(a, b)' + Args: - expression (str | Expression): the SQL code strings to parse. + expression: the SQL code strings to parse. If an Expression instance is passed, this is used as-is. - alias (str | Identifier): the alias name to use. If the name has + alias: the alias name to use. If the name has special characters it is quoted. - table (bool): create a table alias, default false - dialect (str): the dialect used to parse the input expression. + table: Whether or not to create a table alias, can also be a list of columns. + quoted: whether or not to quote the alias + dialect: the dialect used to parse the input expression. **opts: other options to use to parse the input expressions. Returns: @@ -4135,8 +4174,14 @@ def alias_(expression, alias, table=False, dialect=None, quoted=None, **opts): alias = to_identifier(alias, quoted=quoted) if table: - expression.set("alias", TableAlias(this=alias)) - return expression + table_alias = TableAlias(this=alias) + exp.set("alias", table_alias) + + if not isinstance(table, bool): + for column in table: + table_alias.append("columns", to_identifier(column, quoted=quoted)) + + return exp # We don't set the "alias" arg for Window expressions, because that would add an IDENTIFIER node in # the AST, representing a "named_window" [1] construct (eg. bigquery). What we want is an ALIAS node |