postgresqlHow do I use the PostgreSQL COALESCE function?

The PostgreSQL COALESCE function is used to return the first non-null value from a list of values. It takes in any number of arguments and returns the first one that is not NULL.

Example

SELECT COALESCE(NULL, 5, 0);

Output example

5

The code above will return the value 5 because it is the first non-null value in the list.

The parts of the code are:

• SELECT: This is the keyword used to specify that a query is being made.
• COALESCE: This is the function being used to return the first non-null value.
• NULL: This is a value that is being checked for.
• 5: This is the value that is returned because it is the first non-null value.
• 0: This is the last value in the list, but it is not returned because it is not the first non-null value.

For more information on the COALESCE function, please see the following link:

PostgreSQL Documentation

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