count(*) of a union
Hello,
How does the count work if there is a union in the query?
I've tried this but it didn't work giving this error: Every derived table must have its own alias
select count(*)
from
(select cod from table1 UNION cod from table2)
I've also tried this but didn't work:
select count(*)
from
(select cod from table1 UNION select cod from table2)
as table
Thanks in advance
How does the count work if there is a union in the query?
I've tried this but it didn't work giving this error: Every derived table must have its own alias
select count(*)
from
(select cod from table1 UNION cod from table2)
I've also tried this but didn't work:
select count(*)
from
(select cod from table1 UNION select cod from table2)
as table
Thanks in advance
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the second one should work, does that give the same error?
ASKER
it gives this error:
#1064 - 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 'table' at line 4
#1064 - 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 'table' at line 4
ASKER CERTIFIED SOLUTION
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ASKER
yeah! you are right, thanks!
Both should work (depending upon the need to name the derived table).
Perhaps you want UNION ALL. UNION will filter out the duplicate rows.
Good Luck,
Kent