Question

I have 5 tables in my Mysql database with t1 with field name like data,id,cool and 4 other tables with id and data say t2,t3,t4,t5.

I have used join and sub queries but result i am getting is empty set its not mandatory that all the fields in the t2,t3,t4,t5 tables are populated .t4,t5,t3,t2 can be empty i am using where clause on data if data column of t1 = t2 = t3 = t4 = t5 if it finds any matching data in any of the table it prints the cool from t1 and id and data from found table if any and if founds the data match in all the table it prints all the table stats like

cool data.t1 id.t1
cool data.t2 id.t2 
and so on



table t1

cool data id
0    xyz   1

table t2

data id
xyz   5

table t3

data id
xyz   4

table t4

data id
xyz   3

table t5

data id
xyz   2

desired output

cool data id
  0   xyz  1
  0   xyz  4
  0   xyz  3
  0   xyz  5
  0   xyz  2

if any of the table is empty say t5 and t4 than output should be

 cool data id
  0   xyz  1
  0   xyz  4
  0   xyz  3

Answer 1

What i understand from the question is you need to get data from table t1 for all other tables for all matching data and id column in respective table.

A simple way to achieve is to join each table with t1 seperately and then use union all to combine all results.

SELECT t1.cool, t2.data, t2.id
FROM t1 INNER JOIN t2 ON (t1.id=t2.id) AND (t1.data=t2.data)
UNION ALL
SELECT t1.cool, t3.data, t3.id
FROM t1 INNER JOIN t3 ON (t1.id=t3.id) AND (t1.data=t3.data)
UNION ALL
SELECT t1.cool, t4.data, t4.id
FROM t1 INNER JOIN t4 ON (t1.id=t4.id) AND (t1.data=t4.data)
UNION ALL
SELECT t1.cool, t5.data, t5.id
FROM t1 INNER JOIN t5 ON (t1.id=t5.id) AND (t1.data=t5.data)

---

as from your example, it is quite possible that there can be duplicate records To filter them out use distinct like this –

SELECT DISTINCT cool, data, id
FROM
(
-- above query here
)