Question

I am writing a DB upgrade script that will check to see if an index has the right two columns defined. If it doesn’t, or if it only has one of them, then I will DROP it (is there a way to ALTER an index?) and then recreate it with both.

Answer 1

I don’t have a database immediately on-hand to test this, but you should be able to see if a column exists in an index by using the following IF EXISTS statement.

I’m not sure whether you can alter an index on the fly.

IF EXISTS (    SELECT MyIndex.Name AS IndexName,            Columns.name AS ColumnName     FROM sys.indexes MyIndex    INNER JOIN sys.index_columns IndexColumns        ON  MyIndex.index_id = IndexColumns.index_id       AND MyIndex.object_id = IndexColumns.object_id     INNER JOIN sys.columns Columns       ON  Columns.column_id = IndexColumns.column_id        AND IndexColumns.object_id = Columns.object_id     WHERE Columns.name = 'ColumnName'    AND MyIndex.Name='IX_MyIndexName' )