Questions:
I have 2 tables:
Table : Movies
MovieID -- Name
1 -- Movie1
2 -- Movie2
Table: Types
MovieID -- Type
1 -- DVD
1 -- Bluray
1 -- VCD
2 -- DVD
I need a query to find out this in one row:
Movie1 : DVD – Bluray – VCD
I used:
SELECT Movies.Name,
IF(TYPE = 'DVD', 1, 0 ) AS DVD,
IF(TYPE = 'Bluray', 1, 0 ) AS Bluray,
IF(TYPE = 'VCD', 1, 0 ) AS VCD
FROM Movies LEFT JOIN Types ON Movies.MovieID = Types.MovieID
But it return multiplate lines:
Movies.Name -- DVD -- Bluray -- VCD
Movie1 -- 1 -- 0 -- 0
Movie1 -- 0 -- 1 -- 0
Movie1 -- 0 -- 0 -- 1
Movie2 -- 1 -- 0 -- 0
I want:
Movie1 -- 1 -- 1 -- 1
Movie2 -- 1 -- 0 -- 0
How to&Answers:
The group_concat() function might do the trick, here.
Not tested, but I suppose something like this should work :
SELECT Movies.Name,
group_concat(type separator ' - ') as type
FROM Movies
LEFT JOIN Types ON Movies.MovieID = Types.MovieID
group by Movies.Name
Answer：
Assuming you want separate columns returned for each type:
SELECT m.Name,
SUM(CASE WHEN t.Type = 'DVD' THEN 1 ELSE 0 END) AS DVD,
SUM(CASE WHEN t.Type = 'Bluray' THEN 1 ELSE 0 END) AS Bluray,
SUM(CASE WHEN t.Type = 'VCD' THEN 1 ELSE 0 END) AS VCD
FROM Movies m
LEFT JOIN Types t
ON m.MovieID = t.MovieID
GROUP BY m.Name
Answer：
SELECT m.Name, IF(t1.Type IS NOT NULL, 1, 0) as DVD, IF(t2.Type IS NOT NULL, 1, 0) as Bluray, IF(t3.Type IS NOT NULL, 1, 0) as VCD FROM Movies m LEFT OUTER JOIN Types t1 on m.MovieID = t1.MovieID and t1.Type = 'DVD' LEFT OUTER JOIN Types t2 on m.MovieID = t2.MovieID and t2.Type = 'Bluray' LEFT OUTER JOIN Types t3 on m.MovieID = t3.MovieID and t3.Type = 'VCD'
