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what is outer join?
what is selef join?
what is difference between them?
what is cartecion join?

Answer Posted / nandini sett

Outer join displays result set containing all the rows from
one table and the matching rows from another table. There
are three types of Outer Join -- Left Outer Join (All rows
of the left table and matchng rows of the right), Right
Outer Join (All rows of the right table and matching rows
of the left table) and Full Outer Join (All rows of both
tables).
In self join, table is joined with itself. One row
correlates with other rows in the same table. Hence a table
name with two alias names is used.
Difference between outer join and self join is that outer
join uses atleast two or more tables where one column is
common while self join uses only one table and two fields
of the same table.
Cartesian Product or cross join is between two tables where
each row from one table with each row of the other table.
If table A has 5 rows and table B has 10 rows then after
cross join the total number of rows would be 50.

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