T-SQL Select join with condition

join, max, sql-server, t-sql

Solution

There are several ways that you can get the result. You can use a subquery to get the `max(modificationdate)`:

select c.id, r.colorname
from cars c
inner join CarColorhistory h1
  on c.id = h1.carid
inner join
(
  select max(modificationdate) MaxDate,
    carid
  from CarColorhistory
  group by carid
) h2
  on h1.carid = h2.carid
  and h1.modificationdate = h2.maxdate
inner join color r
  on h1.colorid = r.id

See SQL Fiddle with Demo

Or since you are using SQL Server you can use ranking functions:

select id, colorname
from
(
  select c.id, r.colorname,
    row_number() over(partition by c.id order by modificationdate desc) rn
  from cars c
  inner join CarColorhistory h1
    on c.id = h1.carid
  inner join color r
    on h1.colorid = r.id
) src
where rn = 1;

See SQL Fiddle with Demo

Problem

Lets say that i have a 3 tables: Cars - Id CarColorHistory - Id - CarID - ColorID - ModificationDate Color: - Id - ColorName I want to select all cars and their colors but the important thing is, that color for the car is the last modified color from `CarColorHistory` table. I need to use join to do this. Example: Cars: ``` 1 2 ``` CarColorhistory: ``` 1 1 1 26/03/2012 -> (actual color, can be take by date or id) 2 1 2 25/03/2012 3 2 2 25/03/2012 ``` Color: ``` 1 Blue 2 Red ``` I need to get result: (car id, colorName) ``` 1 Blue 2 Red ``` I tried make it by joining Cars table and CarColorHistory table but I get cars for all colors. I need only actual color (last added). Please help

Original source