摘要：
SET nocount ON USE tempdbgo IF ( OBJECT_ID('t1') IS NOT NULL ) DROP TABLE t1CREATE TABLE t1 ( n INT )INSERT INTO t1 SELECT 2 UNIO... 阅读全文
摘要：
原来join=inner join，left/right/full join=left/right/full outer join。join/inner join仅返回匹配的left outer join返回左边每一项，右边不匹配的就null，right反之full outer join返回左右的，... 阅读全文