SQL OR vs AND
In SQL, the OR and AND operators are used to combine multiple conditions in the WHERE clause of a query to filter and retrieve data from a database table. However, they have different logical behaviors:
1.OR Operator:
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SELECT * FROM employees WHERE department = 'Sales' OR salary > 50000; |
This query retrieves all employees who are either in the “Sales” department or have a salary greater than $50,000.
2.AND Operator:
- The
ANDoperator returns true only if all the conditions it combines are true.It is used to narrow down the query results, retrieving rows that meet all of the specified conditions.When usingAND, all conditions must evaluate to true for the entire condition to be true.
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SELECT * FROM orders WHERE order_date >= '2023-01-01' AND order_date <= '2023-12-31' AND total_amount > 1000; |
This query retrieves orders placed in the year 2023 with a total amount greater than $1000. All three conditions must be met for a row to be included in the result.
Here’s a summary of the key differences:
ORbroadens the query results, whileANDnarrows them down.- With
OR, at least one condition must be true for the entire expression to be true. - With
AND, all conditions must be true for the entire expression to be true.
You can also use parentheses to control the order of evaluation when combining AND and OR operators in more complex queries to ensure the desired logic is applied.
