Use CONCAT inside CONCAT in mysql - mysql

Question

I have a stored procedure and a part of it is:
SET #TableAlias = " ls_flock AS _flk ";
SET #Select = CONCAT(
" _flk.Id as Id, _flk.Code as Code, ",
CONCAT(" _em.FirstName", " ", "_em.LastName "), -- here I want to CONCAT 2 columns as one field.
" as FlockManager"
);
SET #Join = " JOIN employee as _em ON _flk.EmployeeId = _em.Id ";
I am unable to CONCAT two columns as a field with a CONCAT function.
And if I remove following line, code works fine:
CONCAT(" _em.FirstName", " ", "_em.LastName "), -- here I want to CONCAT 2 columns as one field.
" as FlockManager"
I'm getting this error:
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 '.LastName as FlockManager FROM ls_flock AS _flk JOIN employee as _em ON _flk.' at line 1

Answer 1

I suspect that you want to generate a query string that uses CONCAT() - because I see that the table alias _em is declared further in the #Join variable. For this, you would need to move the function inside the query string.
SET #Select = CONCAT(
" _flk.Id as Id, ",
"_flk.Code as Code, ",
"CONCAT(_em.FirstName, "" "", _em.LastName) s FlockManager"
;
And then, you just don't need the outer CONCAT():
SET #Select =
" _flk.Id as Id, _flk.Code as Code, CONCAT(_em.FirstName, "" "", _em.LastName) as FlockManager";