Question

I am running this query

SELECT *  
FROM (`T_INV_DTL`)  
LEFT JOIN 
 (
  SELECT GROUP_CONCAT(DISTINCT T_INV_INVESTIGATOR.Employee_id) AS Employee_id
  FROM T_INV_INVESTIGATOR
  GROUP BY  `T_INV_INVESTIGATOR`.`inv_dtl_id`
  ) ON  `T_INV_DTL`.`inv_dtl_id` =  `T_INV_INVESTIGATOR`.`inv_dtl_id`
JOIN  `T_INVESTIGATION` ON  `T_INV_DTL`.`inv_id` =  `T_INVESTIGATION`.`inv_id` 

and it is giving this error:

#1248 – Every derived table must have its own alias

What is wrong ?

Answer 1

You have to give an alias to subquery,

Check this:

SELECT * 
FROM T_INV_DTL T  
LEFT JOIN ( SELECT inv_dtl_id , GROUP_CONCAT( DISTINCT Employee_id ) AS Employee_id 
            FROM T_INV_INVESTIGATOR 
            GROUP BY inv_dtl_id ) A ON T.inv_dtl_id = A.inv_dtl_id 
JOIN T_INVESTIGATION TI ON T.inv_id = TI.inv_id