[英]sql sum of sums of two tables
如何從兩個表中得到兩個總和?
SELECT (SELECT SUM(col) FROM table1) + SELECT (SUM(col) from table2)
不起作用
你很親密 您只需要在每個子查詢周圍添加括號:
SELECT (SELECT SUM(col) FROM table1) + (SELECT SUM(col) from table2)
如果任何一個子查詢都可以返回NULL
,則您可能更喜歡:
SELECT COALESCE(t1.s, 0) + COALESCE(t2.s)
FROM (SELECT SUM(col) as s FROM table1) t1 CROSS JOIN
(SELECT SUM(col) as s from table2) t2;
由於此鏈接 ,您可以通過以下方法實現:
SELECT T1C1 , T2C1
FROM
( select SUM(Col1) T1C1 FROM T1 ) A
CROSS JOIN
( select SUM(Col1) T2C1 FROM T2 ) B
您也可以訪問以下鏈接:
select coalesce(sum(x),0) from
(
Select sum(a) x from tab1
Union all
Select sum(b) from tab2
) Ilv
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