postgresqlHow do I use the PostgreSQL NVL function?

The PostgreSQL NVL function is used to replace a NULL value with an alternate value. This is useful in cases where you want to avoid errors caused by NULL values. The syntax for the NVL function is as follows:

NVL(expression1, expression2)

where expression1 is the expression to check for NULL values, and expression2 is the value to replace the NULL value with. For example:

SELECT NVL(NULL, 'foo');

This will return foo as the output.

The NVL function can also be used with numerical values. For example:

SELECT NVL(NULL, 0);

This will return 0 as the output.

You can also use the NVL function with other expressions. For example:

SELECT NVL(NULL, 5 + 6);

This will return 11 as the output.

The NVL function is a useful tool for replacing NULL values in PostgreSQL.

Helpful links

• PostgreSQL Documentation
• w3resource

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