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SQL for beginners

Combining conditions with AND #

Sometimes one condition isn't enough. The AND keyword lets you combine multiple conditions in a WHERE clause, keeping only the rows where all of them are true.

Syntax #

SELECT
    column_name
FROM
    table_name
WHERE
    condition_1
    AND condition_2;

A row is only included if condition_1 and condition_2 are both true.

Example #

SELECT
    *
FROM
    customers
WHERE
    gender = 'F'
    AND age > 65;

Result:

+----+------------+-----------+-----+--------+
| id | first_name | last_name | age | gender |
+----+------------+-----------+-----+--------+
| 2  |  Jonathan  |   Dixon   | 71  |   F    |
| 4  |    Juan    |  Campos   | 99  |   F    |
| 8  |   Tammy    |   Woods   | 86  |   F    |
+----+------------+-----------+-----+--------+

Kyle, who is 'F' but only 62 years old, is filtered out because she fails the second condition. You can chain more than two conditions by adding more AND keywords.

Exercise #

Write a query that retrieves all columns from the customers table, keeping only the rows where gender is 'F' and age is greater than 65.

  • The result has an age column.
  • The result contains exactly the rows where gender is 'F' and age is greater than 65, and no others.
Solution 
SELECT
    *
FROM
    customers
WHERE
    gender = 'F'
    AND age > 65;
Output will be displayed here