How to make simple SQL request in mySQL?

Question

please help me guys!

My code doesn't work :( Where is my error?

SELECT * from dummy_table where `a` + `b` + `c` like '99'; 

I have empty return although there are some rows where sum of (a,b,c) gives 99.

a is integer while b,c are DOUBLE. Could this lead into an issue?

Answer 1

You should have a mathematical comparison in your WHERE clause

SELECT * FROM dummy_Table WHERE a + b + c = 99

If you are concerned that the double may contain a small precision that you want to disregard when comparing then round the columns with doubles to your preferred precision, for instance 2 decimals.

SELECT * FROM dummy_Table WHERE a + ROUND(b,2) + ROUND(c,2) = 99

Answer 2

It looks like you are trying to sum a,b,c as letters not as columns. Try removing the single quotes.

Is '99' the full match? You could also try '%99%' if it makes sense in your case.