Query to check index on a table

Question

I need a query to see if a table already has any indexes on it.

Answer 1

Most modern RDBMSs support the INFORMATION_SCHEMA schema. If yours supports that, then you want either INFORMATION_SCHEMA.TABLE_CONSTRAINTS or INFORMATION_SCHEMA.KEY_COLUMN_USAGE, or maybe both.

To see if yours supports it is as simple as running

select count(*) from INFORMATION_SCHEMA.TABLE_CONSTRAINTS

EDIT: SQL Server does have INFORMATION_SCHEMA, and it's easier to use than their vendor-specific tables, so just go with it.