What are the syntax and use of the COALESCE function?

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The syntax of COALESCE function:

COALESCE(exp1, exp2, …. expn)
The COALESCE function is used to return the first non-null expression given in the parameter list.

The COALESCE function in SQL is used to return the first non-null expression among its arguments. It takes multiple arguments and returns the first non-null expression from the list.

Here is the syntax for the COALESCE function:

COALESCE(expression1, expression2, ..., expression_n)
  • expression1, expression2, ..., expression_n: These are the expressions that the COALESCE function evaluates. It returns the value of the first expression that is not NULL.

Here’s an example to illustrate how COALESCE works:

SELECT COALESCE(column1, 'N/A') AS result
FROM your_table;

In this example, if column1 is not NULL, it will be returned. If column1 is NULL, then ‘N/A’ will be returned.

The COALESCE function is often used to provide a default value when a column might contain NULL values.

Keep in mind that the number of arguments in the COALESCE function can vary based on your specific use case.