mysql - Multiple condition in a single SUMIF function -

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select ifnull(sum(if(a=1 , b=2, 'correct', null)),0) table

please using such function above in query. although works want know if right way of handling multiple conditions within 1 single query in mysql. thanks

no. not correct. cannot sum string value. mysql convert number. because 'correct' starts letter, query return 0.

i think intend:

select sum(if(a=1 , b=2, 1, 0)) correct table

note gets rid of outer ifnull(). suggest using coalesce() rather if() because ansi standard functionality. however, conditional not needed.

the query can further simplified. in fact, best way write query is:

select count(*) table = 1 , b = 2;

in general, better write queries conditions in where clause rather in conditional statements (if possible). reduces number of rows rest of query needs process.


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