In SQL, the AND
and OR
operators are used to combine multiple conditions in a WHERE
clause to filter rows from a database table. They control the logical relationships between these conditions.
Here's an explanation of the differences between AND
and OR
operators:
AND Operator:
Logical AND: The
AND
operator is a logical operator that requires all specified conditions to be true for a row to be included in the result set. In other words, it creates a more restrictive filter.Example: If you use the
AND
operator to combine two conditions, Condition A and Condition B, the result will only include rows that satisfy both Condition A and Condition B.SELECT * FROM table_name WHERE Condition_A AND Condition_B;
The row must meet both Condition A and Condition B to be selected.
Truth Table: The result of the
AND
operator is true only when both of its operands are true. The truth table forAND
is as follows:true AND true
=> truetrue AND false
=> falsefalse AND true
=> falsefalse AND false
=> false
OR Operator:
Logical OR: The
OR
operator is a logical operator that requires at least one of the specified conditions to be true for a row to be included in the result set. In other words, it creates a less restrictive filter.Example: If you use the
OR
operator to combine two conditions, Condition A and Condition B, the result will include rows that satisfy either Condition A or Condition B or both.SELECT * FROM table_name WHERE Condition_A OR Condition_B;
The row can meet either Condition A or Condition B to be selected.
Truth Table: The result of the
OR
operator is true if at least one of its operands is true. The truth table forOR
is as follows:true OR true
=> truetrue OR false
=> truefalse OR true
=> truefalse OR false
=> false
Usage:
- Use
AND
when you want to create a more restrictive condition where all specified criteria must be met. - Use
OR
when you want a less restrictive condition and you're interested in rows that meet any of the specified criteria.
Here's an example to illustrate the difference:
SELECT *
FROM products
WHERE (category = 'Electronics' AND price > 100)
OR (category = 'Clothing' AND color = 'Red');
This SQL statement selects products that are either in the 'Electronics' category and have a price over 100 or are in the 'Clothing' category and are red in color, showing the use of both AND
and OR
operators together.
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