Turning a column in to a string - mysql

Question

I want to make 1 query but it is hit by performance issues due to this warning:
Warning: #1292 Truncated incorrect DOUBLE value: ''
See I have this query:
SELECT b.ID,
(SELECT SUM(case when ABBO != '0' then 1 else 0 end)
FROM OCCASIONS where HBODBED = b.ID) as BEOORDELINGEN,
(SELECT SUM(case when ABBO != '0' then ABBO else 0 end)
FROM OCCASIONS where HBODBED = b.ID) as TOTAAL
FROM BEDRIJVEN b WHERE ACTIVE = '1' AND GROEP = '0'
ORDER BY APERC DESC LIMIT 0, 50;
But HBODBED is a varchar(30) and b.ID is a bigint(20)
so lets run a single query:
SELECT SUM(case when ABBO != '0' then ABBO else 0 end) as total,
SUM(case when ABBO != '0' then 1 else 0 end) AS BEOORDELINGEN
FROM OCCASIONS where HBODBED = 59;
still gets warnings and execution time is 0.6498 seconds not bad but if you run 2 of those 50 times it adds up
But if I add string markers to 59 like this: '59' it removes the warnings and the execution time is reduced to 0.0078 seconds so my question is:
How can I add those string markers to b.ID in the top query?

Answer 1

You have this join condition:
WHERE HBODBED = b.ID
where you are comparing varchar(30) with a bigint. MySQL will convert both operands to floating-point numbers and compare them. Besides conversion, the comparison of floating point numbers itself is an expensive operation.
The correct solution is to convert the datatype of columns so that they match. If that is not an option, you can try converting one of the operands:
WHERE HBODBED = CAST(b.ID AS char)
WHERE CAST(HBODBED AS signed) = b.ID
Now only one of the operands is converted. When converting to bigint you will still get "truncated incorrect INTEGER value" warning for values that did not convert to float earlier.