合并两个表并填写mysql中缺少的值
我在MySQL中有以下两个表: 表1:合并两个表并填写mysql中缺少的值,mysql,Mysql,我在MySQL中有以下两个表: 表1: ID Val1 1 100 2 200 3 300 表2: ID Val2 2 50 我怎样才能把它们组合成这样一张桌子呢 ID Val1 Val2 1 100 0 2 200 50 3 300 0 使用LEFT JOIN与IFNULL()一起为Val2填充零 SELECT Table1.ID, Table1.Val1, IFNULL(Table2.Val2, 0) AS Val2 FROM Table1 LEFT
ID Val1
1 100
2 200
3 300
表2:
ID Val2
2 50
我怎样才能把它们组合成这样一张桌子呢
ID Val1 Val2
1 100 0
2 200 50
3 300 0
使用
LEFT JOIN
与IFNULL()
一起为Val2填充零
SELECT
Table1.ID,
Table1.Val1,
IFNULL(Table2.Val2, 0) AS Val2
FROM Table1 LEFT JOIN Table2 ON Table1.ID = Table2.ID
SELECT
Table1.ID,
Table1.Val1,
IFNULL(Table2.Val2, 0) AS Val2
FROM Table1 LEFT JOIN Table2 ON Table1.ID = Table2.ID
SELECT Table1.ID, Table1.Val1, COALESCE(Table2.Val2, 0) AS Val2
FROM Table1 LEFT OUTER JOIN Table2 USING (ID)
INTO NewTable