Question

我的SQL Server中有三个表

1。）注册它的列

   Reg_Id     bigint, primary key and auto increment
   Name       nvarchar(50),
   Tranx_id   nvarchar(30),
   Email      nvarchar(30),
   Username   nvarchar(30),
   Password   nvarchar(30),
   Edition_Id nvarchar(50),
   Default_Id nvarchar(50),
   Reg_Date   datetime,
   usertype   nvarchar(50),

2。）AllEditionPages它的列

Page_id       bigint, primary key and auto increment
edition_date  datetime,
noofpages     int,
Page_no     int,
image_path  nvarchar(50),
Active   int,
type_of_page  varchar(50),
Image_Width  int,
Image_Height int,

3。）版

id  int, primary key and auto increment
edition_date  datetime,
noofpages  int,
XMLFile  nvarchar(50),
PDFFile  nvarchar(50),
PDFPrefix nvarchar(50),
type   nvarchar(50),
price  nvarchar(50),
reg_req nvarchar(50)

如上表所示，我尝试下面的SQL查询

    SELECT edi.*, aep.*, reg.*
    FROM Edition as edi INNER JOIN Registration as reg 
    ON edi.id = reg.Edition_Id INNER JOIN AllEditionPages as aep
    ON edi.edition_date = aep.edition_date
    where reg.Edition_Id= edi.id
    and reg.Reg_ID = 14

从这个查询我得到这个输出：

id    edition_date              type    price  page-id

96    2012-07-18 00:00:00.000   free    null    2503
96    2012-07-18 00:00:00.000   free    null    2503

我输出两行，但只想输出

中的单行

Answer 1

您可以通过以下方式在此方案中使用common table expression：

 WITH cteTable AS
    (
        SELECT edi.*, aep.*, reg.*
        FROM Edition as edi INNER JOIN Registration as reg 
        ON edi.id = reg.Edition_Id INNER JOIN AllEditionPages as aep
        ON edi.edition_date = aep.edition_date
        where reg.Edition_Id= edi.id
        and reg.Reg_ID = 14
    )
    select top 1 * from cteTable

由于您的两个表包含edition_date，您需要指定列名而不是使用“*”，如下所示：

WITH cteTable AS
    (
        SELECT edi.id,edi.edition_date,edi.noofpagez,edi.XMLFile,edi.PDFFile ,edi.PDFPrefix,edi.type,edi.price,edi.reg_req ,
        aep.Page_id, aep.edition_date,aep.noofpages,aep.Page_no,aep.image_path,aep.Active,aep.type_of_page,aep.Image_Width,aep.Image_Height,
        reg.Reg_Id,reg.Name,reg.Tranx_id,reg.Email,reg.Username,reg.Password,reg.Edition_Id,reg.Default_Id,reg.Reg_Date,reg.usertype
        FROM Edition as edi INNER JOIN Registration as reg 
        ON edi.id = reg.Edition_Id INNER JOIN AllEditionPages as aep
        ON edi.edition_date = aep.edition_date
        where reg.Edition_Id= edi.id
        and reg.Reg_ID = 14
    )
    select top 1 * from cteTable

Answer 2

如果2行具有相同的值，您可以使用select distinct，或者您可以在查询后面使用LIMIT 0,1。

Answer 3

您必须指定一行。从您的putput看起来您有重复的数据，如果这是问题，您应该使用distinct来获取不同的行。否则指定您需要的内容。

从sql中的表中获取单个数据？

3 个答案: