Question

I have two tables

    table1                   table2
    numID|counts|date        numID|net|tax|date
    1        1   xy            1    2   1   xy
    2        1   xy            2    2   1   xy
    3        1   xy            3    2   1   xy
    3        1   xy            4    1   1   xy
    4        0   xy    

So I’d need to sum (net + tax) on table2 for rows that have same date,numID and counts=1.
I tried to do where clause but numID 3 would be added two times but i need it to sum only once. numID 4 should be omitted because it has counts=0.
My select:

SELECT 
    SUM(`net`+`tax`) 
FROM table1 AS d, `table2` AS c
WHERE d.date=c.date
    AND d.numID=c.numID
    AND `it_counts` = 1

This adds numID 3 two times but it should be DISTINCT.

Answer 1

Try rewriting this statement with a correlated exists query:

SELECT
    SUM(`net`+`tax`) 
FROM `table2` AS c
WHERE EXISTS (
    SELECT 1 FROM table1 AS d
    WHERE d.date=c.date
        AND d.numID=c.numID
        AND `it_counts` = 1)