2013年12月9日
关于count(1) 和 count(*)
摘要： Q:What is the difference between count(1) and count(*) in a sql queryeg.select count(1) from emp; andselect count(*) from emp;A:nothing, they are the same, incur the same amount of work -- do the same thing, take the same amount of resources.You can see this via:ops$tkyte@ORA817.US.ORACLE.COM> al 阅读全文
posted @ 2013-12-09 18:17 xcf007 阅读(411) 评论(0) 推荐(0)