如何从表中选择记录，其中记录具有与另一个表最相似的属性

Question

TABLE A
result select
A a
B a
B b
C a
C b
C c

TABLE B

user select

1 a
1 b
2 b
2 c

TABLE C
user result
1 B
2 C


what mysql query should i have to use, if i want to do like this:

if user select a the result is ABC (because ABC have 'a' in column 'select') if user select ab the result is BC (because A doesn't have 'b' in column 'select') if user select abc the result is C (because C have 'abc' in column 'select') if user select bc the result is C (because AB doesn't have 'c' in column 'select') if user select c the result is C (because AB doesn't have 'c' in column 'select')

so it will select the record that have the most similar from what user selected and ignore the other record that doesn't match.. sorry for my english, i'm speak bahasa...

Answer 1

SELECT  `result`
FROM tableA
WHERE   `select` IN ('a','b','c')
GROUP BY result
HAVING COUNT(*) = 3

if a unique constraint was not enforce on select for every result , a DISTINCT is required.

SELECT  `result`
FROM tableA
WHERE   `select` IN ('a','b','c')
GROUP BY result
HAVING COUNT(DISTINCT `select`) = 3