20 Jan
2016
20 Jan
'16
11:24 a.m.
Dear experts,
I have columns coming from two different datasets which also resides in two different tables in the same layout,now i need the difference of that columns.
Example: sql>select (select mag from one_to_many o, targets16 t where o.new_targetid=t.id) - (select mag from one_to_many o,targets16 t where o.old_uniqueid=t.id) ; cardinality violation (22>1)
p.s. these two tables have both 22 rows.
But if I subtract on single values, it works:
select (select avg(mag) from mag1) - (select avg(mag) from mag2);
+--------------------------+
| sql_sub_L1 |
+==========================+
| -0.015908087452235264 |
+--------------------------+
1 tuple (4.486ms)
can any one help me out?
Thanks In Advance !!!!
Meng