SQL DISTINCT/GROUP BY不能正常工作

Question

忍耐与我在这里，我对SQL很陌生。我有下面的查询写出来，但DISTINCT基本上被我的WHERE语句否定。这是由于表格中的日期后跟一个时间戳，所以如果订单项放置时间有差异，它会生成一个新行。

什么是最好的方式让它完全忽略日期后的所有内容，以便不会因时间戳而生成新行？从我发现的情况来看，我认为使用GROUP BY可以更好地实现，但接缝总是会产生错误（很可能我不知道将聚合函数放在哪里）。

任何帮助将不胜感激。谢谢！

Select DISTINCT 
so.num AS Ref 
, so.shiptoname AS Recipient_Full_Name 
, so.shiptoaddress AS Address_1 
, so.shiptocity AS City 
, stateconst.name AS State 
, so.shiptozip AS Zip 
, so.billtoname AS Buyer_Name 
, qbclass.name AS Class 
, soitem.datescheduledfulfillment AS Fulfillment_Date 
From SO 
JOIN stateconst 
ON so.shiptostateid=stateconst.id 
JOIN qbclass 
ON so.qbclassid=qbclass.id 
JOIN soitem 
ON so.id=soitem.soid 
WHERE DATESCHEDULEDFULFILLMENT LIKE '2016-05-10%' 

Answer 1

使用CAST()到datetime数据类型更改为date类型：

Select DISTINCT 
so.num AS Ref 
, so.shiptoname AS Recipient_Full_Name 
, so.shiptoaddress AS Address_1 
, so.shiptocity AS City 
, stateconst.name AS State 
, so.shiptozip AS Zip 
, so.billtoname AS Buyer_Name 
, qbclass.name AS Class 
, CAST(soitem.datescheduledfulfillment as date) AS Fulfillment_Date 
From SO 
JOIN stateconst 
ON so.shiptostateid=stateconst.id 
JOIN qbclass 
ON so.qbclassid=qbclass.id 
JOIN soitem 
ON so.id=soitem.soid 
WHERE CAST(soitem.datescheduledfulfillment as date) = '2016-05-10' 

Answer 2

你真的需要在查询输出的日期？因为离开它会解决您的“问题”：

Select DISTINCT 
so.num AS Ref 
, so.shiptoname AS Recipient_Full_Name 
, so.shiptoaddress AS Address_1 
, so.shiptocity AS City 
, stateconst.name AS State 
, so.shiptozip AS Zip 
, so.billtoname AS Buyer_Name 
, qbclass.name AS Class 

From SO 
JOIN stateconst 
ON so.shiptostateid=stateconst.id 
JOIN qbclass 
ON so.qbclassid=qbclass.id 
JOIN soitem 
ON so.id=soitem.soid 
WHERE DATESCHEDULEDFULFILLMENT LIKE '2016-05-10%'