How to Work with NULL Values in CARTO Datasets

Learn how to select, populate or delete NULL values in CARTO datasets.

Replacing NULL values

To replace all NULL values in a column, use the COALESCE PostgreSQL function. This example replaces null with 0 for number-type columns:

UPDATE table_name SET column = COALESCE(column, 0)

If your column is string-type, enclose the second COALESCE argument in single quotes.

Converting values to NULL

You can use NULLIF to replace non-null values with NULL ones:

UPDATE populated_places SET pop_max = NULLIF(pop_max, -99)

Ordering NULL values

Use the PostgreSQL instructions NULLS FIRST or NULLS LAST to define where NULL values appear in results:

SELECT
    cartodb_id,
    column
FROM
  table_name
ORDER BY
  column DESC NULLS LAST