为什么这样简单的SQL都没法出结果.郁闷

''與null是不同的

strCom = "SELECT id,subject,txt,qtime,rtime,rtxt,stuid FROM t3 where rtxt=null "
也不行啊...晕死.

strCom = "SELECT id,subject,txt,qtime,rtime,rtxt,stuid FROM t3 where rtxt='' or rtxt is null"

strCom = "SELECT * FROM t3 where rtxt=null or rtxt=''";

strCom = "SELECT id,subject,txt,qtime,rtime,rtxt,stuid FROM t3 where rtxt='' "


''与NULL是不同的概念

应该是

strCom = "SELECT id,subject,txt,qtime,rtime,rtxt,stuid FROM t3 where rtxt is null "

上面有写“=”肯定不行