Question

Conditional Joining in MySql

Answer 1

SELECT
        (CASE Table1.product
            WHEN 'column_value'
            THEN Table2.COL
            WHEN 'column_value2'
            THEN Table4.sms_count
            ELSE Table3.plan
        END) as ColumnName1,Table1.*
  FROM Table1
     INNER JOIN Table2
        ON Table2.id = Table1.product_id
    INNER JOIN Table3
        ON Table3.id = Table1.product_id
     INNER JOIN Table4
        ON Table4.id = Table1.product_id;