關於select語句的書寫,瞭解執行順序很有必要,用下面的例子做介紹:
select from where group by having order by 中,
首先執行的是from後的語句,說明數據的來源;
-->執行where後的語句,對記錄進行初步篩選;
-->執行group by後的語句,對初步篩選後剩下的字段進行分組;
-->執行having後的語句,對分組後的記錄進行二次篩選;
-->執行select後的語句,在二次篩選後的字段中進行選擇並顯示出來;
-->執行order by後的語句,對select 後的字段進行排序。
2. 這個select 語句要怎麼寫如果你想計算每日的訂單總額應該是:
sql="select Date,sum(TotalPrice) as Total_Price from Statistics where Date between #" & FirstDate & "# And #" & EndDate & "# and Factory='"&Factory&"' group by Date order by Date desc"
如果你想要更多新資訊:
sql="select Pono,Date,Style,Customer,Factory,sum(TotalPrice) as Total_Price from Statistics where Date between #" & FirstDate & "# And #" & EndDate & "# and Factory='"&Factory&"' group by Pono,Date,Style,Customer,Factory,id order by id desc"
select後非聚集運算Column必須出現在group by後。