Question

I want to extract data from multiple independent tables with no relationship .
Tables are tbl_temp1, tbl_temp2, tbl_temp3, tbl_temp4,so on
Every tables have common fields ie id,value,timestamp
But the records are independent in every tables so there is no relationship between them.

I want to generate values of all tables horizontally
ie-
Value_of_tbl_temp1 | Value_of_tbl_temp2 | Value_of_tbl_temp3 | Value_of_tbl_temp4 | …
| | | |

with no duplicates of data

Please help me with the solution.

Answer 1

SELECT un.common_id, COALESCE(t1_value), COALESCE(t2_value), COALESCE(t3_value) FROM
(SELECT t1.common_id, t1.value as t1_value, NULL AS t2_value, NULL AS t3_value FROM t1
UNION 
SELECT t2.common_id, NULL, t2.value, NULL FROM t2
UNION 
SELECT t3.common_id, NULL, NULL, t3.value FROM t3) AS un
GROUP BY un.common_id