LEFT JOIN 数据库左连接查询SQL

-- 普通查询

SELECT T1.NAME , T2.ORDERNO

FROM TABLE_NAME1 T1 , TABLE_NAME T2

WHERE T1.ID = T2.T1_ID

AND T1.STATUS = '1';

-- LEFT JOIN查询

SELECT T1.NAME , T2.ORDERNO

FROM TABLE_NAME1 T1

LEFT JOIN TABLE_NAME T2

ON T1.ID = T2.T1_ID

AND T1.STATUS = '1';

注释:LEFT JOIN 左连接查询会以主表为查询主体,查询出另外一张表相对应的数据行,即使没有数据也会返回空的数据行!