SQL：结合两个 sql 查询

Question

I have two tables:

T_CHAMBRE_CHB (CHB_NUM); 

T_PLANNING_PLN (PLN_JOUR ,CHB_NUM, PLN_LIBRE);

I have these values in it:

T_CHAMBRE_CHB:

1
2
3
4

T_PLANNIG_CHB:

1   2000-01-12  1   False
2   2000-01-12  2   False
3   2000-01-13  1   False
4   2000-01-13  2   False
5   2000-01-13  4   True 

I would like to get the rooms occpation the 13 janvier 2000 for information if a room is not in the planning (here 3) that's mean it's free, so the result should be:

CHB_NUM     PLN_LIBRE 
----------- --------- 
1           False
2           False
3           True 
4           True 

I have this query:

SELECT DISTINCT TCC.CHB_NUM, TPP.PLN_LIBRE
FROM T_CHAMBRE_CHB AS TCC,
     T_PLANNING_PLN AS TPP
WHERE TCC.CHB_NUM=TPP.CHB_NUM AND TPP.PLN_JOUR  = '2000-01-13'
UNION
SELECT DISTINCT TCC.CHB_NUM, TPP.PLN_LIBRE
FROM T_CHAMBRE_CHB AS TCC,
     T_PLANNING_PLN AS TPP
WHERE TCC.CHB_NUM NOT IN (SELECT DISTINCT (TPP2.CHB_NUM) FROM T_PLANNING_PLN AS TPP2);

I get this result:

1   1   False
2   2   False
3   3   False
4   3   True 
5   4   True 

I don't know why I get the third line ( 3---->False )

I think I should use an OUTER UNION but SQL Server doesn't like the syntax.

Answer 1

You have to use left join if I am understanding your question.

Please use below query may be it helps you

SELECT T_CHAMBRE_CHB.CHB_NUM, ISNULL(T_PLANNIG_CHB.PLN_LIBRE, FALSE)
FROM T_CHAMBRE_CHB
LEFT JOIN T_PLANNIG_CHB ON (T_CHAMBRE_CHB.CHB_NUM = T_PLANNIG_CHB.CHB_NUM)
WHERE T_PLANNIG_CHB.PLN_JOUR = '2000-01-13'

Answer 2

Below query might give the required result :-

declare @date as date='2000-01-13'

select distinct TCC.CHB_NUM,COALESCE(TPP.PLN_JOUR,@date) PLN_JOUR,COALESCE(TPP.PLN_LIBRE,'True') PLN_LIBRE    
from T_CHAMBRE_CHB TCC
LEFT OUTER JOIN
T_PLANNING_PLN TPP ON TCC.CHB_NUM=TPP.CHB_NUM
WHERE TPP.PLN_JOUR=@date OR TPP.PLN_JOUR IS NULL

Output :-

 CHB_NUM    PLN_JOUR    PLN_LIBRE
    1      2000-01-13   False
    2      2000-01-13   False
    3      2000-01-13   True
    4      2000-01-13   True