oracle數據庫對test_table表的三個列count1,count2,count3求sum的兩種sql,做個記錄
第一種
select sum (case when count1 is not null then count1 when
count2 is not null then count2 when count3 is not null
then count3 else '0' end ) a from test_table
第二種
select sum(decode(count1,null,0,count1) +decode(count2,null,0,count2)
+decode(count3,null,0,count3)) a from test_table