SELECT
Name,
COALESCE(LifeExpectancy, 100) LifeExpectancy
FROM country
| Name | LifeExpectancy |
| Aruba | 78.4 |
| Afghanistan | 45.9 |
| Angola | 38.3 |
| Anguilla | 76.1 |
| Albania | 71.6 |
| Andorra | 83.5 |
| Netherlands Antilles | 74.7 |
| United Arab Emirates | 74.1 |
| Argentina | 75.1 |
| Armenia | 66.4 |
| ... |
| In the example, the average life expectancy in each country is selected. If there is no data, the value is set to 100 years. COALESCE(expression1, expression2, ..., expressionN) The function returns the first non-empty value from the list of arguments. If all arguments are NULL, returns NULL. expression1, expression2, ..., expressionN are expressions that are checked sequentially until a non-empty value is found. |