Is it normal to do UNION 8 times) will it generally affect the speed?

Question

SQL

Is it normal to do UNION 8 times) does it affect the speed at all?
And is it possible to specify one WHERE for all unions, since the field is the same.

Answer 1

No, it's not normal. Already one union is most likely govnokod and and curve structure of a DB.
The speed is affected not by some particularly dangerous operators, but by the enumeration of large amounts of data without an index.