I have to display ten columns values from diffrent ten
tables.
how many joins are require?
Answers were Sorted based on User's Feedback
Answer / praveen mehta
There are 2 possible answers
1. No joins required
Ex:
SELECT Col1 As Col from Tab1
Union
SELECT Col2 As Col from Tab2
Union
SELECT Col1 As Col from Tab3
...
2. 9 Joins Required
Ex:
SELECT
t1.Col1,
t2.Col2,
....
FROM Tab1 t1
inner join Tab2 t2 on t1.Col1=t2.Col2
inner join Tab3 t3 on t1.Col1=t3.Col2
....
Is This Answer Correct ? | 44 Yes | 2 No |
Answer / anil sharma
If there is no relation between tables then no joins.And if
there relation and you want to fetch related data then 9
join required if parent table has all foreign key of their
tables.
Is This Answer Correct ? | 29 Yes | 2 No |
Answer / nitin
there are 3 answeres
1. No joins are required if do not want to display related
data
2. 9 joins are requred if all tables are related
3. no joins reuquired we can use union if condition is
like following
select cola from a
union
select colb from b
union
select colc from c
.
.
.
like wise ten statements
Is This Answer Correct ? | 8 Yes | 2 No |
Answer / b.kumar
--MS SQL SERVER
WE CAN DISPLAY RECORDS BY USING 9 JOINS
SELECT TBL1.COLUMN1,TBL2.COLUMN2,---------,TBL10.COLUMN10
FROM TBL1 INNER JOIN TBL2 ON TBL1.ID=TBL2.ID
INNER JOIN TBL3 ON TBL1.ID=TBL3.ID
----
----
----
INNER JOIN TBL10 ON TBL1.ID=TBL10.ID
----------------------------------------
--WE CAN ALSO DISPLAY THE RECORDS WITH OUT USE JOINS
SELECT TBL1.COLUMN1,TBL2.COLUMN2,---------,TBL10.COLUMN10
FROM TBL1,TBLE2,--------,TBL10
WHERE TBL1.ID=TBL2.ID OR TBL1.ID=TBL3.ID OR
----
----
----
TBL1.ID=TBL10.ID
--WE MUST USE WHERE CLAUSE OTHER WISE WE GET Cartesian product.
--------------------------------------------------
WE CAN'T JOIN DIFFERENT TABLES OF COLUMNS BY USING UNION
BECAUSE UNION COMBINES THE TWO OR MORE RESULT SETS
(IT MEANS ROWS)
DIFFERENCE BETWEEN JOIN & UNION
-- JOIN COMBINES TWO OR MORE THE COLUMNS
-- UNION COMBINES TWO OR MORE ROWS
Is This Answer Correct ? | 0 Yes | 0 No |
Answer / ask
Select column1, column2, ...., column10 from table1,
table2, ..., table10
Is This Answer Correct ? | 2 Yes | 3 No |
Answer / sumesh.s.g
n-1 JOINS
that is 10-1 Join
Or using UNION or UNION all but its not a join
However we will get value from Tables
Is This Answer Correct ? | 2 Yes | 3 No |
Answer / sathish
The 10 tables can be joined as,
select table1.columnname,table2.columnname,.....
from table1,table2,.......
It displays 10 fields from 10 different tables.
Is This Answer Correct ? | 3 Yes | 5 No |
Answer / sanjay kumar dinda
It will be 9( no. of tables -1)...
As we can join two tables by using two tables ...
Is This Answer Correct ? | 0 Yes | 2 No |
Answer / sachin
i Think there is formula 2n-1
where n is the number of table
so, answer will be 2*10-1=19
Is This Answer Correct ? | 2 Yes | 13 No |
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