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Editorial Team
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Asked: 2026-06-05T15:32:44+00:00

Is there any significance in the order of table in sql join statement. For

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Is there any significance in the order of table in sql join statement. For example

SELECT dept_name, emp_name 
FROM   Employee 
INNER JOIN Department ON Employee.dept_id = Department.dept_id

and

SELECT dept_name, emp_name 
FROM Department 
INNER JOIN Employee  ON Employee.dept_id = Department.dept_id

Is there is any performance advantage in the order of tables?

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1 Answer

  1. Editorial Team

    No there isn’t.

    Most (if not all) DBMS’s use of a Cost based optimizer. The order in which you specify your statements does not affect speed of execution.

    Oracle SQL cost based optimization

    Oracle’s cost-based SQL optimizer (CBO) is an extremely sophisticated
    component of Oracle that governs the execution for every Oracle query.
    The CBO has evolved into one of the world’s most sophisticated
    software components, and it has the challenging job of evaluating any
    SQL statement and generating the “best” execution plan for the
    statement.

    Both your statements will generate the same execution plan and hence have the same perfomance characteristics. Note that the cost will be based on available statistics. Updated statistics is very important for the optimizer to be able to generate the most efficient execution plan.

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