查错(这句查询语句应如何写)
这句话是:select * from AdviceListView where roomcode=2000 and sendopecode>0
and exectime>''
and exectime<''
and patname like '%'
and medname like '%'
and offcode =''
order by intime desc
这是我在VB中按键用的语句,其中只有当OFFCODE为空时,查询不到数据,为什么呢?请各位帮我看一下,