Mysql 中联接SQL语句中,ON子句的语法格式为:table1.column_name = table2.column_name。 当模式设计对联接表的列采用了相同的命名样式时,就可以使用 USING 语法来简化 ON 语法,格式为:USING(column_name)。 例如:SELECT f.color, c.is_primary, c.is_dark, c.is_rainbow FROM flags f www.2cto.com INNER JOIN color c ON f.color = c.color WHERE f.country = 'China'; 等价于SELECT f.color, c.is_primary, c.is_dark, c.is_rainbow FROM flags f INNER JOIN color c USING(color) WHERE f.country = 'China';
直接查看帮助文档 讲得很清楚但是在一般情况下没必要用USING
select * from tableA inner join tableB on tableA.id=tableB.id select * from tableA inner join tableB on using(id)
当模式设计对联接表的列采用了相同的命名样式时,就可以使用 USING 语法来简化 ON 语法,格式为:USING(column_name)。
例如:SELECT f.color, c.is_primary, c.is_dark, c.is_rainbow
FROM flags f www.2cto.com
INNER JOIN color c ON f.color = c.color
WHERE f.country = 'China';
等价于SELECT f.color, c.is_primary, c.is_dark, c.is_rainbow
FROM flags f
INNER JOIN color c USING(color)
WHERE f.country = 'China';
select * from tableA inner join tableB on using(id)