- Inner Join
- Outer Join
- Left Outer Join
Right Outer Join
- Full Outer Join
- Cross Join
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Joins in SQL Server allows the retrieval of data records from one or more tables having some relation between them. Logical operators can also be used to drill down the number of records to get the desired output from sql join queries.
- Inner Join: Inner Join is a default type join of SQL Server. It uses logical operators such as =, <, > to match the records in two tables. Inner Join includes equi join and natural joins.
Examples:
SQL Inner Join Examples
SQL Inner Natural Join Examples
SQL Inner Equi Join Examples
- Outer Join: Outer Join has further 3 sub categories as left, right and full. Outer Join uses these category names as keywords that can be specified in the FROM clause.
- Left Outer Join: Left Outer Join returns all the rows from the table specified first in the Left Outer Join Clause. If in the left table any row has no matching record in the right side table then that row returns null column values for that particular tuple.
Examples:
SQL Left Outer Join Examples - Right Outer Join: Right Outer Join is exactly the reverse method of Left Outer Join. It returns all the rows from right table and returns null values for the rows having no match in the left joined table.
Examples:
SQL Right Outer Join Examples - Full Outer Join: Full outer join returns all the rows from both left and right joined tables. If there is any match missing from the left table then it returns null column values for left side table and if there is any match missing from right table then it returns null value columns for the right side table.
Examples:
SQL Full Outer Join Examples - Cross Join: Cross join works as a Cartesian product of rows for both left and right table. It combined each row of left table with all the rows of right table.
Puneet Sharma
Monday, August 22, 2011
Type of Joins in Sql Server 2005
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