一对多连接中的限制记录

Question

I'm trying to generate a list of records where the header contains a single record and the FIRST entry in the log denotes the creation date of the record. All other detail records are unnecessary and create multiple results when I only need the first.

I've tried "group by", self joins, distinct, etc, but so far nothing I've done has the intended effect. I feel like I'm missing something really obvious here.

This is what I'm working with:

SELECT i.id
    ,l.CreateDate
    ,i.departmentname
    ,i.productkey
    ,c.Description
FROM dbo.table i (NOLOCK)

JOIN dbo.log l ON i.id = l.id

JOIN dbo.LU_Table c ON i.id = c.ID

WHERE l.CreateDate > '2019-04-01'

AND l.CreateDate < '2019-04-30'

I would like to see:

ID# 1, 04/05/2019, Department, Product, Description
ID# 2, 04/05/2019, Department, Product, Description
ID# 3, 04/05/2019, Department, Product, Description
ID# 4, 04/05/2019, Department, Product, Description

Instead, I get:

ID# 1, 04/05/2019, Department, Product, Description
ID# 1, 04/06/2019, Department, Product, Description
ID# 1, 04/07/2019, Department, Product, Description
ID# 1, 04/08/2019, Department, Product, Description
ID# 1, 04/09/2019, Department, Product, Description
ID# 2, 04/05/2019, Department, Product, Description
ID# 2, 04/06/2019, Department, Product, Description
ID# 2, 04/07/2019, Department, Product, Description
ID# 2, 04/08/2019, Department, Product, Description
ID# 2, 04/09/2019, Department, Product, Description

Answer 1

The easiest way i think would be to put Order By after your where clause. so it would look like ORDER BY l.CreateDate, i.id ASC and that should do the trick.

Answer 2

You would seem to want:

SELECT i.id, l.CreateDate, i.departmentname, i.productkey, c.Description
FROM dbo.table i JOIN
     (SELECT l.id, MIN(l.CreateDate) as CreateDate
      FROM dbo.log l
      GROUP BY l.id
     ) l
     ON i.id = l.id JOIN
     dbo.LU_Table c
     ON i.id = c.ID
WHERE l.CreateDate > '2019-04-01' AND
      l.CreateDate < '2019-04-30';

Answer 3

What I understood from query is that there are the table name table i has single record for id and the log table may have multiple record against each ID .

You can achieve this by creating a derived table for log table.

Derived Table

Select  row_number() over(partition by ID order by ID) srno     
          , ID 
          , creation_date
   From log

Try this

SELECT i.id
    ,l.CreateDate
    ,i.departmentname
    ,i.productkey
    ,c.Description
FROM dbo.table i (NOLOCK)
JOIN (Select  row_number() over(partition by ID order by ID) srno       
              , ID 
              , creation_date
       From log ) l  on l.id = i.id and  l.srno = 1

JOIN dbo.LU_Table c ON i.id = c.ID
WHERE l.CreateDate > '2019-04-01'

AND l.CreateDate < '2019-04-30'