Question

How we can group the result of the query depending up on the parameter passed.

A small stored procedure is shown below. parameter Param is passed to the procedure.

If param value is “f” the result must group by starttime otherwise by using formid. How can i do this. ???I tried the code show below but its not working .

DROP PROCEDURE IF EXISTS Test;
CREATE PROCEDURE Test (Param VARCHAR (2))


 BEGIN
  SELECT formid, starttime
    FROM tbevaluationscoreinfo
   CASE Param
     when 'F'
      then group by starttime;
     else
      group by formid;

   end
END;

Answer 1

One way is to move branching up a level:

IF Param = 'F' THEN
  SELECT starttime, count(formid)
  FROM tbevaluationscoreinfo
  GROUP BY starttime;
ELSE
  SELECT formid, count(starttime)
  FROM tbevaluationscoreinfo
  GROUP BY formid;
END IF;

Another, less recommended solution, is dynamic SQL.

And the third possible solution is:

SELECT
  case Param when 'F' then starttime else formid end as group_column,
  count(formid),
  count(starttime)
FROM
  tbevaluationscoreinfo
GROUP BY
  group_column;