# phpman > man > CREATE_CONVERSION(7)

CREATE [CONVERSION(7)](https://www.chedong.com/phpMan.php/man/CONVERSION/7/markdown)               PostgreSQL 14.23 Documentation               CREATE [CONVERSION(7)](https://www.chedong.com/phpMan.php/man/CONVERSION/7/markdown)



## NAME
       CREATE_CONVERSION - define a new encoding conversion

## SYNOPSIS
       CREATE [ DEFAULT ] CONVERSION _name_
           FOR _source_encoding_ TO _dest_encoding_ FROM _function_name_

## DESCRIPTION
       **CREATE** **CONVERSION** defines a new conversion between two character set encodings.

       Conversions that are marked DEFAULT can be used for automatic encoding conversion between
       client and server. To support that usage, two conversions, from encoding A to B _and_ from
       encoding B to A, must be defined.

       To be able to create a conversion, you must have EXECUTE privilege on the function and CREATE
       privilege on the destination schema.

## PARAMETERS
       DEFAULT
           The DEFAULT clause indicates that this conversion is the default for this particular
           source to destination encoding. There should be only one default encoding in a schema for
           the encoding pair.

       _name_
           The name of the conversion. The conversion name can be schema-qualified. If it is not,
           the conversion is defined in the current schema. The conversion name must be unique
           within a schema.

       _source_encoding_
           The source encoding name.

       _dest_encoding_
           The destination encoding name.

       _function_name_
           The function used to perform the conversion. The function name can be schema-qualified.
           If it is not, the function will be looked up in the path.

           The function must have the following signature:

               conv_proc(
                   integer,  -- source encoding ID
                   integer,  -- destination encoding ID
                   cstring,  -- source string (null terminated C string)
                   internal, -- destination (fill with a null terminated C string)
                   integer,  -- source string length
                   boolean   -- if true, don't throw an error if conversion fails
               ) RETURNS integer;

           The return value is the number of source bytes that were successfully converted. If the
           last argument is false, the function must throw an error on invalid input, and the return
           value is always equal to the source string length.

## NOTES
       Neither the source nor the destination encoding can be SQL_ASCII, as the server's behavior
       for cases involving the SQL_ASCII “encoding” is hard-wired.

       Use **DROP** **CONVERSION** to remove user-defined conversions.

       The privileges required to create a conversion might be changed in a future release.

## EXAMPLES
       To create a conversion from encoding UTF8 to LATIN1 using **myfunc**:

           CREATE CONVERSION myconv FOR 'UTF8' TO 'LATIN1' FROM myfunc;

## COMPATIBILITY
       **CREATE** **CONVERSION** is a PostgreSQL extension. There is no **CREATE** **CONVERSION** statement in the
       SQL standard, but a **CREATE** **TRANSLATION** statement that is very similar in purpose and syntax.

## SEE ALSO
       ALTER CONVERSION (**ALTER**___**[CONVERSION**(7)](https://www.chedong.com/phpMan.php/man/CONVERSION/7/markdown)), CREATE FUNCTION (**CREATE**___**[FUNCTION**(7)](https://www.chedong.com/phpMan.php/man/FUNCTION/7/markdown)), DROP CONVERSION
       (**DROP**___**[CONVERSION**(7)](https://www.chedong.com/phpMan.php/man/CONVERSION/7/markdown))



PostgreSQL 14.23                                2026                            CREATE [CONVERSION(7)](https://www.chedong.com/phpMan.php/man/CONVERSION/7/markdown)