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

On SQL Server, this will list all the indexes for a specified table:

select * from sys.indexes
where object_id = (select object_id from sys.objects where name = 'MYTABLE')

This query will list all tables without an index:

SELECT name
FROM sys.tables 
WHERE OBJECTPROPERTY(object_id,'IsIndexed') = 0

And this is an interesting MSDN FAQ on a related subject:
Querying the SQL Server System Catalog FAQ

Answer 2

On Oracle:

• Determine all indexes on table:

  SELECT index_name 
   FROM user_indexes
   WHERE table_name = :table
  

• Determine columns indexes and columns on index:

  SELECT index_name
       , column_position
       , column_name
    FROM user_ind_columns
   WHERE table_name = :table
   ORDER BY index_name, column_order
  

References:

• ALL_IND_COLUMNS
• ALL_INDEXES

Answer 3

Created a stored procedure to list indexes for a table in database in SQL Server

create procedure _ListIndexes(@tableName nvarchar(200))
as
begin
/*
exec _ListIndexes '<YOUR TABLE NAME>'
*/
SELECT DB_NAME(DB_ID()) as DBName,SCH.name + '.' + TBL.name AS TableName,IDX.name as IndexName, IDX.type_desc AS IndexType,COL.Name as ColumnName,IC.*
    FROM sys.tables AS TBL 
         INNER JOIN sys.schemas AS SCH ON TBL.schema_id = SCH.schema_id 
         INNER JOIN sys.indexes AS IDX ON TBL.object_id = IDX.object_id 
         INNER JOIN sys.index_columns IC ON  IDX.object_id = IC.object_id and IDX.index_id = IC.index_id 
         INNER JOIN sys.columns COL ON ic.object_id = COL.object_id and IC.column_id = COL.column_id 
        where TBL.name = @tableName
    ORDER BY TableName,IDX.name

end

Answer 4

If you're using MySQL you can run SHOW KEYS FROM table or SHOW INDEXES FROM table

Answer 5

If you just need the indexed columns EXEC sp_helpindex 'TABLE_NAME'

Answer 6

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