'\" t
.\"     Title: DROP FUNCTION
.\"    Author: The PostgreSQL Global Development Group
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 2024
.\"    Manual: PostgreSQL 16.2 Documentation
.\"    Source: PostgreSQL 16.2
.\"  Language: English
.\"
.TH "DROP FUNCTION" "7" "2024" "PostgreSQL 16.2" "PostgreSQL 16.2 Documentation"
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.SH "NAME"
DROP_FUNCTION \- remove a function
.SH "SYNOPSIS"
.sp
.nf
DROP FUNCTION [ IF EXISTS ] \fIname\fR [ ( [ [ \fIargmode\fR ] [ \fIargname\fR ] \fIargtype\fR [, \&.\&.\&.] ] ) ] [, \&.\&.\&.]
    [ CASCADE | RESTRICT ]
.fi
.SH "DESCRIPTION"
.PP
\fBDROP FUNCTION\fR
removes the definition of an existing function\&. To execute this command the user must be the owner of the function\&. The argument types to the function must be specified, since several different functions can exist with the same name and different argument lists\&.
.SH "PARAMETERS"
.PP
IF EXISTS
.RS 4
Do not throw an error if the function does not exist\&. A notice is issued in this case\&.
.RE
.PP
\fIname\fR
.RS 4
The name (optionally schema\-qualified) of an existing function\&. If no argument list is specified, the name must be unique in its schema\&.
.RE
.PP
\fIargmode\fR
.RS 4
The mode of an argument:
IN,
OUT,
INOUT, or
VARIADIC\&. If omitted, the default is
IN\&. Note that
\fBDROP FUNCTION\fR
does not actually pay any attention to
OUT
arguments, since only the input arguments are needed to determine the function\*(Aqs identity\&. So it is sufficient to list the
IN,
INOUT, and
VARIADIC
arguments\&.
.RE
.PP
\fIargname\fR
.RS 4
The name of an argument\&. Note that
\fBDROP FUNCTION\fR
does not actually pay any attention to argument names, since only the argument data types are needed to determine the function\*(Aqs identity\&.
.RE
.PP
\fIargtype\fR
.RS 4
The data type(s) of the function\*(Aqs arguments (optionally schema\-qualified), if any\&.
.RE
.PP
CASCADE
.RS 4
Automatically drop objects that depend on the function (such as operators or triggers), and in turn all objects that depend on those objects (see
Section\ \&5.14)\&.
.RE
.PP
RESTRICT
.RS 4
Refuse to drop the function if any objects depend on it\&. This is the default\&.
.RE
.SH "EXAMPLES"
.PP
This command removes the square root function:
.sp
.if n \{\
.RS 4
.\}
.nf
DROP FUNCTION sqrt(integer);
.fi
.if n \{\
.RE
.\}
.PP
Drop multiple functions in one command:
.sp
.if n \{\
.RS 4
.\}
.nf
DROP FUNCTION sqrt(integer), sqrt(bigint);
.fi
.if n \{\
.RE
.\}
.PP
If the function name is unique in its schema, it can be referred to without an argument list:
.sp
.if n \{\
.RS 4
.\}
.nf
DROP FUNCTION update_employee_salaries;
.fi
.if n \{\
.RE
.\}
.sp
Note that this is different from
.sp
.if n \{\
.RS 4
.\}
.nf
DROP FUNCTION update_employee_salaries();
.fi
.if n \{\
.RE
.\}
.sp
which refers to a function with zero arguments, whereas the first variant can refer to a function with any number of arguments, including zero, as long as the name is unique\&.
.SH "COMPATIBILITY"
.PP
This command conforms to the SQL standard, with these
PostgreSQL
extensions:
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
The standard only allows one function to be dropped per command\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
The
IF EXISTS
option
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
The ability to specify argument modes and names
.RE
.SH "SEE ALSO"
CREATE FUNCTION (\fBCREATE_FUNCTION\fR(7)), ALTER FUNCTION (\fBALTER_FUNCTION\fR(7)), DROP PROCEDURE (\fBDROP_PROCEDURE\fR(7)), DROP ROUTINE (\fBDROP_ROUTINE\fR(7))