Issue using HAVING-Clause: Invalid expression in the select list (not contained in either an aggregate function or the GROUP BY clause) [duplicate] - sql

Question

I am using Firebird SQL. The below mentioned query returns 4 rows as shown in the figure.
SELECT a.EPS_ID,b.C_NAME,c.AY_YR_NAME,d.S_NAME,e.E_NAME
FROM
TBLEXAMPLANNER_S_MSB a,
TBLCLASS_MSB b,
TBLACADEMICYEAR_MSB c,
TBLSUBJECTS_MSB d,
TBLEXAMTYPE_MSB e
WHERE
a.EPS_CLASS_ID=b.C_ID
AND a.EPS_SESSION_ID=c.AY_ID
AND a.EPS_SUB_ID=d.S_ID
AND a.EPS_PE_ID=e.E_ID
I want it to return only 1(one) row like
EPS_ID C_NAME AY_YR_NAME S_NAME E_NAME
---------------------------------------------------
7 5 2016-2017 English FA1
I am using the following query but it does not work.
SELECT a.EPS_ID,MAX(b.C_NAME) AS XT,c.AY_YR_NAME,d.S_NAME,e.E_NAME
FROM
TBLEXAMPLANNER_S_MSB a,
TBLCLASS_MSB b,
TBLACADEMICYEAR_MSB c,
TBLSUBJECTS_MSB d,
TBLEXAMTYPE_MSB e
WHERE
a.EPS_CLASS_ID=b.C_ID
AND a.EPS_SESSION_ID=c.AY_ID
AND a.EPS_SUB_ID=d.S_ID
AND a.EPS_PE_ID=e.E_ID
GROUP BY a.EPS_ID,d.S_NAME
The error message is :
Invalid expression in the select list (not contained in either an
aggregate function or the GROUP BY clause)

Answer 1

The usage of GROUP BY makes the engine group the records for you. To do grouping, you have to give advice to the RDBMS for each column, what it should do.
Group it? -> Add column to GROUP BY-Clause
Not group it? -> ok, what else?
ignore the column? remove it from your select-clause
Sum it? -> use SUM(mycol)
other aggregation functions can be found in the documentation
Additionally: In your case you try to group by EPS_ID, which is unique in each row. So a grouping by that column will return all rows, because there is nothing to group by. To group records, they have to have the same value.

Answer 2

Learn to use proper, explicit JOIN syntax.
Your problem is that all unaggregated columns need to be in the GROUP BY:
SELECT a.EPS_ID, MAX(b.C_NAME) AS XT, c.AY_YR_NAME, d.S_NAME, e.E_NAME
FROM TBLEXAMPLANNER_S_MSB a JOIN
TBLCLASS_MSB b
ON a.EPS_CLASS_ID = b.C_ID JOIN
TBLACADEMICYEAR_MSB c
ON a.EPS_SESSION_ID = c.AY_ID JOIN
TBLSUBJECTS_MSB d
ON a.EPS_SUB_ID = d.S_ID JOIN
TBLEXAMTYPE_MSB e
ON a.EPS_PE_ID = e.E_ID
GROUP BY a.EPS_ID, c.AY_YR_NAME, d.S_NAME, e.E_NAME;
Note: I would also recommend that you use table abbreviations for table aliases. So, ep for TBLEXAMPLANNER_S_MSB instead of a. Arbitrary table aliases make the query hard to follow.

Answer 3

Try
SELECT a.EPS_ID,c.AY_YR_NAME,d.S_NAME,e.E_NAME,MAX(b.C_NAME) AS XT ...
GROUP BY 1,2,3,4