oracle按列求乘积(转)
ID QTY
1 2
2 4
3 6
4 5
要求能够得到QTY字段的乘积2*4*6*5,
运用一下数学知识， 可以这样简化：
a * b * c = power(10, log(10, a) + log(10, b) + log(10, c)
Select power(10, Sum(Log(10, qty))) From t
scott@O9I.US.ORACLE.COM> drop table t;
Table dropped.
scott@O9I.US.ORACLE.COM> create table t (id number, qty number);
Table created.
scott@O9I.US.ORACLE.COM> insert into t values(1, 2);
1 row created.
scott@O9I.US.ORACLE.COM> insert into t values(2, 4);
1 row created.
scott@O9I.US.ORACLE.COM> insert into t values(3, 6);
1 row created.
scott@O9I.US.ORACLE.COM> insert into t values(4, 5);
1 row created.
scott@O9I.US.ORACLE.COM> commit;
Commit complete.
scott@O9I.US.ORACLE.COM> Select power(10, Sum(Log(10, qty))) From t
2 ;
POWER(10,SUM(LOG(10,QTY)))
--------------------------
240
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