mysql - Query in a LIKE-TREE table -


i have table following columns:

idcat, idparent, des

idcat autoincremented, des description , idparent can "0" if record parent or can have "idcat" value of parent if child.

i need query select "des" of record not have child, this:

select des table having count (idcat=idparent) = 0

obviously query doesn't work.

can me please?

this can done via not in, not exists or left join ... null - latter best-performing in mysql:

select t1.des table t1 left join table t2 on t1.idcat = t2.idparent t2.idparent null

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