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如何为下面给出的查询编写等效的SQL case语句?

发布时间:2021-01-20 14:02:57 所属栏目:编程 来源:网络整理
导读:这是我的工作查询: Query = "select Cust_Id,Card_Number,Clients_Title,Address_Current,Phone_Number,Mobile_Number from Customer_New Where 1=1";try{ if (txt_title.Text != "") Query += " and Clients_Title Like '%" + txt_title.Text + "%'"; if (t

这是我的工作查询:

Query = "select Cust_Id,Card_Number,Clients_Title,Address_Current,Phone_Number,Mobile_Number from Customer_New Where 1=1";
try
{
    if (txt_title.Text != "")
        Query += " and Clients_Title Like '%" + txt_title.Text + "%'";
    if (txt_address.Text != "")
        Query += " and Address_Current Like '%" + txt_address.Text + "%'";
    if (txt_phone.Text != "")
        Query += " and Phone_Number Like '%" + txt_phone.Text + "%'";
    if (txt_mobile.Text != "")
        Query += " and Mobile_Number Like '%" + txt_mobile.Text + "%'";
    if (cbo_location.Text != "")
        Query += " and AreaLocation Like '%" + cbo_location.Text + "%'";
}

catch { }

在这里,我试图编写其等效的SQL case语句.

SELECT Cust_Id,Key_Person,Mobile_Number,AreaLocation
FROM Customer_New
    WHERE  1 = CASE WHEN @Clients_Title != " " THEN  Clients_Title  AND
                              WHEN  @Address_Current != " " THEN  Address_Current  AND
                             WHEN  @Phone_Number != " " THEN  Phone_Number AND
                             WHEN  @Mobile_Number != " " THEN  Mobile_Number AND
                             WHEN  @AreaLocation != " " THEN  AreaLocation 
END

任何人都能纠正我的案件陈述吗?

解决方法

我想你只想要这个 – 不需要CASE:
SELECT Cust_Id,AreaLocation
FROM Customer_New
    WHERE
      (@Clients_Title = '' OR Clients_Title LIKE '%'+@Clients_Title+'%') AND
      (@Address_Current = '' OR Address_Current LIKE '%'+@Address_Current+'%') AND
      (@Phone_Number = '' OR Phone_Number LIKE '%'+@Phone_Number+'%') AND
      (@Mobile_Number = '' OR Mobile_Number LIKE '%'+@Mobile_Number+'%') AND
      (@AreaLocation = '' OR AreaLocation LIKE '%'+@AreaLocation+'%')

因为这至少非常类似于非SQL代码.

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