Which function is used to avoid divide by zero errors in SQL?

The function that prevents divide by zero errors in SQL is NULLIF. This function takes two arguments and returns NULL if they are equal; otherwise, it returns the first argument. When you use NULLIF in a division operation, you can effectively handle cases where the denominator might be zero.

For example, if you have an expression like numerator / NULLIF(denominator, 0), if denominator is zero, NULLIF will return NULL, leading the division operation to result in NULL instead of causing a divide-by-zero error. This allows your SQL queries to run smoothly without crashing due to such errors, and it provides a way to handle scenarios gracefully where data might not be as expected.

The other options do have their own purposes but do not specifically address the division by zero issue. For instance, CASE can be used for conditional logic, IS NULL checks for NULL values, and DECODE is typically used for resolving values based on matching comparisons. However, none of these directly prevent division by zero like NULLIF does.