<!--
doc/src/sgml/ref/alter_table.sgml
PostgreSQL documentation
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<refentry id="sql-altertable">
 <indexterm zone="sql-altertable">
  <primary>ALTER TABLE</primary>
 </indexterm>

 <refmeta>
  <refentrytitle>ALTER TABLE</refentrytitle>
  <manvolnum>7</manvolnum>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>ALTER TABLE</refname>
  <refpurpose>change the definition of a table</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
<synopsis>
ALTER TABLE [ IF EXISTS ] [ ONLY ] <replaceable class="parameter">name</replaceable> [ * ]
    <replaceable class="parameter">action</replaceable> [, ... ]
ALTER TABLE [ IF EXISTS ] [ ONLY ] <replaceable class="parameter">name</replaceable> [ * ]
    RENAME [ COLUMN ] <replaceable class="parameter">column_name</replaceable> TO <replaceable class="parameter">new_column_name</replaceable>
ALTER TABLE [ IF EXISTS ] [ ONLY ] <replaceable class="parameter">name</replaceable> [ * ]
    RENAME CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> TO <replaceable class="parameter">new_constraint_name</replaceable>
ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
    RENAME TO <replaceable class="parameter">new_name</replaceable>
ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
    SET SCHEMA <replaceable class="parameter">new_schema</replaceable>
ALTER TABLE ALL IN TABLESPACE <replaceable class="parameter">name</replaceable> [ OWNED BY <replaceable class="parameter">role_name</replaceable> [, ... ] ]
    SET TABLESPACE <replaceable class="parameter">new_tablespace</replaceable> [ NOWAIT ]
ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
    ATTACH PARTITION <replaceable class="parameter">partition_name</replaceable> { FOR VALUES <replaceable class="parameter">partition_bound_spec</replaceable> | DEFAULT }
ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
    DETACH PARTITION <replaceable class="parameter">partition_name</replaceable> [ CONCURRENTLY | FINALIZE ]

<phrase>where <replaceable class="parameter">action</replaceable> is one of:</phrase>

    ADD [ COLUMN ] [ IF NOT EXISTS ] <replaceable class="parameter">column_name</replaceable> <replaceable class="parameter">data_type</replaceable> [ COLLATE <replaceable class="parameter">collation</replaceable> ] [ <replaceable class="parameter">column_constraint</replaceable> [ ... ] ]
    DROP [ COLUMN ] [ IF EXISTS ] <replaceable class="parameter">column_name</replaceable> [ RESTRICT | CASCADE ]
    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> [ SET DATA ] TYPE <replaceable class="parameter">data_type</replaceable> [ COLLATE <replaceable class="parameter">collation</replaceable> ] [ USING <replaceable class="parameter">expression</replaceable> ]
    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET DEFAULT <replaceable class="parameter">expression</replaceable>
    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> DROP DEFAULT
    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> { SET | DROP } NOT NULL
    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET EXPRESSION AS ( <replaceable class="parameter">expression</replaceable> )
    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> DROP EXPRESSION [ IF EXISTS ]
    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> ADD GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ]
    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> { SET GENERATED { ALWAYS | BY DEFAULT } | SET <replaceable>sequence_option</replaceable> | RESTART [ [ WITH ] <replaceable class="parameter">restart</replaceable> ] } [...]
    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> DROP IDENTITY [ IF EXISTS