I need a query to see if a table already has any indexes on it.
check this as well This gives an overview of associated constraints across a database. Please also include facilitating where condition with table name of interest so gives information faster.
select
a.TABLE_CATALOG as DB_name,a.TABLE_SCHEMA as tbl_schema, a.TABLE_NAME as tbl_name,a. CONSTRAINT_NAME as constraint_name,b.CONSTRAINT_TYPE
from INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE a
join INFORMATION_SCHEMA.TABLE_CONSTRAINTS b on
a.CONSTRAINT_NAME=b.CONSTRAINT_NAME