Documentation Home
MySQL 8.4 Reference Manual
Related Documentation Download this Manual
PDF (US Ltr) - 39.8Mb
PDF (A4) - 39.9Mb
Man Pages (TGZ) - 257.9Kb
Man Pages (Zip) - 364.9Kb
Info (Gzip) - 4.0Mb
Info (Zip) - 4.0Mb


MySQL 8.4 Reference Manual  /  ...  /  The INFORMATION_SCHEMA PARAMETERS Table

28.3.20 INFORMATION_SCHEMA PARAMETERS 表

The PARAMETERS table provides information about parameters for stored routines (stored procedures and stored functions), and about return values for stored functions. The PARAMETERS table does not include built-in (native) functions or loadable functions.

The PARAMETERS table has these columns:

  • SPECIFIC_CATALOG

    The name of the catalog to which the routine containing the parameter belongs. This value is always def.

  • SPECIFIC_SCHEMA

    The name of the schema (database) to which the routine containing the parameter belongs.

  • SPECIFIC_NAME

    The name of the routine containing the parameter.

  • ORDINAL_POSITION

    For successive parameters of a stored procedure or function, the ORDINAL_POSITION values are 1, 2, 3, and so forth. For a stored function, there is also a row that applies to the function return value (as described by the RETURNS clause). The return value is not a true parameter, so the row that describes it has these unique characteristics:

    • The ORDINAL_POSITION value is 0.

    • The PARAMETER_NAME and PARAMETER_MODE values are NULL because the return value has no name and the mode does not apply.

  • PARAMETER_MODE

    The mode of the parameter. This value is one of IN, OUT, or INOUT. For a stored function return value, this value is NULL.

  • PARAMETER_NAME

    The name of the parameter. For a stored function return value, this value is NULL.

  • DATA_TYPE

    The parameter data type.

    The DATA_TYPE value is the type name only with no other information. The DTD_IDENTIFIER value contains the type name and possibly other information such as the precision or length.

  • CHARACTER_MAXIMUM_LENGTH

    For string parameters, the maximum length in characters.

  • CHARACTER_OCTET_LENGTH

    For string parameters, the maximum length in bytes.

  • NUMERIC_PRECISION

    For numeric parameters, the numeric precision.

  • NUMERIC_SCALE

    For numeric parameters, the numeric scale.

  • DATETIME_PRECISION

    For temporal parameters, the fractional seconds precision.

  • CHARACTER_SET_NAME

    For character string parameters, the character set name.

  • COLLATION_NAME

    For character string parameters, the collation name.

  • DTD_IDENTIFIER

    The parameter data type.

    The DATA_TYPE value is the type name only with no other information. The DTD_IDENTIFIER value contains the type name and possibly other information such as the precision or length.

  • ROUTINE_TYPE

    PROCEDURE for stored procedures, FUNCTION for stored functions.