I have tables ‘table1', ‘table2’,’table3' and 'table4’ . ’table1’ has a column ‘account’ on basis of I need to get record from 'table2’ or ‘table3’ or ‘table4’ with respect of another column ‘user_id’.
I am using query like
SELECT *
FROM table1
LEFT OUTER JOIN table2 ON table1.user_id = table2.user_id
LEFT OUTER JOIN table2 ON table1.user_id = table2.user_id
LEFT OUTER JOIN table3 ON table1.user_id = table3.user_id
using this I am getting lots of NULL values because each record of table1 will have only record in either ‘table2’ or ‘table3’ or ‘table4’.
Present output is like -
t1.user_id | t1.post_id | t2.token | t3.token | t4.token
1 | 1 | xyz | NULL | NULL
1 | 1 | NULL | abc | NULL
1 | 1 | NULL | NULL | etc
needed is like
t1.user_id | t1.post_id | token
1 | 1 | xyz
1 | 1 | abc
1 | 1 | etc
t2,t3 and t4 can have more than 1 column to select.