SQL statement error
mysql> Select Emp_B AS Total
-> From (Select Sum(mines.NoOfWorkers) AS Emp_B from mines);
ERROR 1248 (42000): Every derived table must have its own alias
mysql> Select Emp_B AS Total
-> From (Select Sum(mines.NoOfWorkers) from mines) AS Emp_B;
ERROR 1054 (42S22): Unknown column 'Emp_B' in 'field list'
I am having some prob开发者_开发问答lem with this SQL statement. Any assistance will be mose appreciated
Select Emp_B AS Total
From (Select Sum(mines.NoOfWorkers) AS Emp_B from mines) x;
As the error states Every derived table must have its own alias
Just give it an alias, like x
above. OR AS x
, but the AS
word is optional.
Or why alias it twice...
Select Total
From (Select Sum(mines.NoOfWorkers) AS Total from mines) x;
But since SUM gives you exactly one value, unless you have simplified the query from some larger one, this gives exactly the same result??
Select Sum(mines.NoOfWorkers) AS Total from mines;
This should work for you; however, if you're only doing this one sub select into a temp table it's kind of a waste to wrap it into another select but that's just IMHO.
Select Emp_B.sum From (Select Sum(mines.NoOfWorkers) as sum from mines) AS Emp_B;
Select temp.total
From
( Select Sum(mines.NoOfWorkers) AS total
from mines
) AS temp
;
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