Combining Conditions with AND/OR

Real-world queries often need multiple conditions. SQL provides AND and OR to combine them.

AND - All Conditions Must Match

SELECT * FROM users WHERE condition1 AND condition2;

Both conditions must be true for a row to be included.

OR - Any Condition Can Match

SELECT * FROM users WHERE condition1 OR condition2;

A row is included if either condition is true.

Exercises

Order of Operations

Without parentheses, AND is evaluated before OR:

-- This:
WHERE a OR b AND c
-- Is interpreted as:
WHERE a OR (b AND c)

Use parentheses to make your intent clear.

Free Practice

Try building queries that:

• Find young users from big cities
• Find users matching several possible criteria
• Experiment with parentheses to see how they change results