mysql - How to create left joins without repetition of rows on the left side -
i have scenario there 2 tables (tables , b) linked in 1 many relationship. row in table a, maximum number of linked rows in b two, , these 2 rows (if exist) different each other through type column value either x or y.
aid | name bid | type | aid 1 | name1 1 | x | 1 2 | name2 2 | x | 2 3 | name3 3 | y | 2
now, want have join query 2 tables in such way rows in displayed (no repetition) , 2 columns called type x , type y hold boolean / integer value show existence of types x , y each row in a. i.e,
aid | name | type x | type y | 1 | name1 | x | null | 2 | name2 | x | y | 3 | name3 | null | null |
my dbms mysql.
thanks.
you have use 2 joins:
select a.*, b1.type typex, b2.type typey left join b b1 on a.aid = b1.aid , b1.type = 'x' left join b b2 on a.aid = b2.aid , b2.type = 'y'
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