SELECT column_name(s) FROM table1 LEFT JOIN table2 ON table1.column_name = table2.column_name; Note: In some databases LEFT JOIN is called LEFT OUTER JOIN.Demo DatabaseIn this tutorial we will use the well-known Northwind sample database....
左连接条件和where条件过滤器不相同。在完成物理联接之后，数据由where子句过滤。如果你看一个左连接，它...
左连接条件和where条件过滤器不相同。在完成物理联接之后，数据由where子句过滤。如果你看一个左连接，它...
JOIN:添加外部行,如果指定了LEFT JOIN(LEFT OUTER JOIN),则先遍历一遍左表的每一行,其中不在vt2的行会被插入到vt2,该行的剩余字段将被填充为NULL,形成vt3;如果指定了RIGHT JOIN也是同理。但如果指定的是INNER JOIN,则不会添加外部行,上述插入过程被忽略,vt2=vt3(所以INNER JOIN的过滤条件放在ON或WHERE里 执行...
to my knowledge, abap opensql supports only 'inner join' and 'left outer join'. dont forget to reward points , and if you have something to share, please do. cheers, Aditya. Reply suresh_datti Active Contributor In response to former_member184495 2006 Jan 21 2:59 PM 0 Kudos ...
SELECT * FROM table1 JOIN table2 SELECT * FROM table1,table2 由于其返回的结果为被连接的两个数据表的乘积,因此当有WHERE, ON或USING条件的时候一般不建议使用,因为当数据表项目太多的时候,会非常慢。 一般使用LEFT [OUTER] JOIN或者RIGHT [OUTER] JOIN ...
Hive的left join、left outer join和left semi join三者的区别 join测试数据 测试1:left join 语句: select * from table1 left outer join table2 on(table1.student_no=table2...student_no); 结果: FAILED: Parse Error: line 1:22 cannot recognize input near ‘left’ ‘join’ ‘table2’ in......
Hive的left join、left outer join和left semi join三者的区别 join测试数据 测试1:left join 语句: select * from table1 left outer join table2 on(table1.student_no=table2...student_no); 结果: FAILED: Parse Error: line 1:22 cannot recognize input near ‘left’ ‘join’ ‘table2’ in......