Mysql sub-query return null

Question

Hi I am a beginner I am trying to make all the result row of my subquery that is null to return 0 not null. but I am getting an error. I will really appreciate any advice. Thank you

Error Code: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'AS 'Income'

SELECT  

 COUNT(DISTINCT t1.id) AS 'Val1',


     COALESCE((SELECT SUM(CAST(COALESCE(r.t_payment_total,0) AS DECIMAL(18,2))) AS 'Income'
FROM reserv r
INNER JOIN newtbladds1 t ON t.t_parent_id = r.id
 WHERE r.t_status!="Pending" && r.t_status!="Booked" AND r.c_mid = m.id AND  t.t_type_id = t1.t_type_id 
 ),0)AS 'Income'



 FROM tbladds1 t1
JOIN tbladds1_type tt ON tt.id = t1.t_type_id
JOIN tbladdress m ON m.id = t1.t_mid
JOIN tbladdressfr mf ON mf.id = t1.t_floor_id
JOIN tblppl mp ON mp.t_mid = m.id AND mp.t_type = 'try' AND mp.t_system_id = 'ok'
GROUP BY t1.t_tool_type_id
ORDER BY m.t_m ASC, tt.t_ttype ASC, mf.t_floor ASC;

Output I removed COALESCE I am having null

Val1           Income
10              Null
2               30
23              10
5               Null

Desired Output

Val1           Income
10              0
2               30
23              10
5               0

Answer 1

I would suggest moving that subquery into the from clause

SELECT
    t1.t_tool_type_id
  , COUNT( DISTINCT t1.id ) AS `Val1`
  , COALESCE(i.Income , 0 ) AS `Income`
FROM tbladds1 t1
JOIN tbladds1_type tt ON tt.id = t1.t_type_id
JOIN tbladdress m ON m.id = t1.t_mid
JOIN tbladdressfr mf ON mf.id = t1.t_floor_id
JOIN tblppl mp ON mp.t_mid = m.id
    AND mp.t_type = 'try'
    AND mp.t_system_id = 'ok'
left join (
        SELECT
             CAST( SUM(r.t_payment_total) AS decimal(18, 2) ) AS `Income`
        FROM reserv r
        INNER JOIN newtbladds1 t ON t.t_parent_id = r.id
        WHERE r.t_status != 'Pending'
        AND r.t_status != 'Booked'
        AND r.c_mid = m.id
        GROUP BY
            t.t_type_id
    ) as i on t1.t_type_id = i.t_type_id
GROUP BY
    t1.t_tool_type_id
;

nb: I have assumed r.t_payment_total is numeric.

I also suggest you always use single quotes for values/literals, and in MySQL backticks for identity (eg column headings) but really they are not essential in this query.