摘要:
报错内容:A connection was successfully established with the server, but then an error occurred during the pre-login handshake. (provider: TCP Provider, er 阅读全文
摘要:
wm_concat(列名),该函数可以把列值以","号分隔起来,并显示成一行 准备测试数据SQL> create table test(id number,name varchar2(20));SQL> insert into test values(1,'a');SQL> insert into 阅读全文
摘要:
SQL存在一个表而不在另一个表中的数据方法一使用 not in ,容易理解,效率低select distinct A.ID from A where A.ID not in (select ID from B) www.2cto.com 方法二使用 left join...on... , "B.ID 阅读全文