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mysqlsqlsql-serverauto-increment

SQL - Check if a column auto increments


I am trying to run a query to check if a column auto increments. I can check type, default value, if it's nullable or not, etc. but I can't figure out how to test if it auto increments. Here is how I am testing for those other things:

SELECT *
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = 'my_table'
AND COLUMN_NAME = 'my_column'
AND DATA_TYPE = 'int'
AND COLUMN_DEFAULT IS NULL
AND IS_NULLABLE = 'NO'
--AND AUTO_INCREMENTS = 'YES'

Unfortunately there is no AUTO_INCREMENTS column to compare against. So how can I test if a column auto increments?


Solution

  • For MySql, Check in the EXTRA column:

    SELECT *
    FROM INFORMATION_SCHEMA.COLUMNS
    WHERE TABLE_NAME = 'my_table'
        AND COLUMN_NAME = 'my_column'
        AND DATA_TYPE = 'int'
        AND COLUMN_DEFAULT IS NULL
        AND IS_NULLABLE = 'NO'
        AND EXTRA like '%auto_increment%'
    

    For Sql Server, use sys.columns and the is_identity column:

    SELECT 
        is_identity
    FROM sys.columns
    WHERE 
        object_id = object_id('my_table')
        AND name = 'my_column'