What is a self join ?
Answers were Sorted based on User's Feedback
Answer / anil_abbireddy
A table is joined itself is called self join or Self
referential integrity.
| Is This Answer Correct ? | 12 Yes | 0 No |
Answer / rupesh.dbms@gmail.com
It is the join in which result is obtained by equating two
coloumns with same values of one table for example
emp(eno,ename,mgrno) eno is primary key and mgrno is
recursive foreign key
select e.eno,e.ename,m.mgrno,m.ename mgrname
from emp e, emp m
where m.eno=e.mgrno;
note : one table emp is replicated as m , e and then
result is obtained.
| Is This Answer Correct ? | 9 Yes | 1 No |
Answer / anbu
Self join is defined as a table is viewd by two different
ways and then the join can be done with the same table.
By another way the definition is 'A table can be joined
with itself using sel join'.
| Is This Answer Correct ? | 7 Yes | 1 No |
Answer / ram
Normally we joins for retrieve data from more than 1 table
In some cases we need to join 1 table itself to join itself
condition is table having two column with same data type &
size but name are different
In emp table empno & mgrno are two columns example for this
select ename,job,sal,e.empno,m.mgrno from emp e inner join
emp m on m.mgrno=e.empno
| Is This Answer Correct ? | 2 Yes | 2 No |
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