6. 连接查询中的冲突 如果您在连接查询(JOIN Query,请参见https://javarevisited.blogspot.com/2012/11/how-to-join-three-tables-in-sql-query-mysql-sqlserver.html#axzz5az3hfsHW)中使用了SELECT * ,那么一旦在多个表中出现了具有相同名称的列,例如status、active和name等,就可能会产生各种并发式的冲突。
例如:如果您可能是在本地计算机上运行由SQL Server Management Studio(请详见http://bit.ly/2CXPyBB)、Toad或SQL Developer for Oracle(请参见http://bit.ly/2xQzAsd)提供的查询编辑器,或是在某个Java应用服务器上运行此类查询,这都会耗费您不少的网络流量与资源。 3.更多的应用内存 随着业务数据的猛增,您的...
I'm afraid my version of TOAD is ancient (7.6.0.11) and doesn't seem to have a query builder function - not that I can see, anyway. This thread is the result of my not having had any formal training in this and having to pick things up on the job while being left to my own d...