項目中,由於需要把3個狀態的任務合並顯示,並且按照任務由近及遠的順序排序,類似於下面的語句
select * from (select top 100 percent taskid,state from looptask where state=1 order by taskid desc )m union all select * from (select top 100 percent taskid,state from looptask where state=2 order by taskid desc )n union all select * from (select top 100 percent taskid,state from looptask where state=3 order by taskid desc )t
但是在執行中,發現結果並沒有按照設定的排序顯示。
后來發現這個方法可行,把100改成99.9999999 這樣使用select top 99.999999 PERCENT,一般來說,你的數據庫不超過1億條數據,使用99.999999 PERCENT都不會使你遺漏數據。需要的話再添倆9