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COALESCE function

June 20, 2023, 7:17 p.m. under SQL
    • Hi! You should check NULLIF function post first.

    In SQL, the COALESCE function is used to return the first non-null expression/value in a list of expressions/values.

    The syntax of the COALESCE function generally looks like this :
    COALESCE(expression1, expression2, expression3, ...)

    • Define the 'expression1', 'expression2', 'expression3' and so on.

    Here's an example of how you might use the COALESCE function :

    1. Consider a sequence of values comprising NULL, NULL, 1, and 2.

    2. Run below SQL statement :

    SELECT COALESCE(NULL, NULL, 1, 2) AS Result;

    3. In this example, the query successfully retrieves the first non-null value which is number '1' from the series of inputs given to COALESCE.

    COALESCE function
    To enhance your understanding of 'SQL functions', be sure to check out our next tutorial.

    Frequently Asked Questions :

    What is the function of coalesce in SQL?
     

    COALESCE in SQL returns the first non-null value among its arguments.

    How do I coalesce two columns in SQL?
     

    To coalesce two columns in SQL, you use the COALESCE function with those columns as arguments.

    What are the differences between coalesce () and Isnull () in SQL?
     

    The difference between COALESCE() and ISNULL() in SQL is that COALESCE() can take multiple parameters and returns the first non-null value, while ISNULL() is specific to SQL Server and only replaces null values with a specified replacement.

    What is nullif and coalesce in SQL?
     

    NULLIF in SQL returns null if the two specified expressions are equal, while COALESCE returns the first non-null expression among its arguments.
    Thank You! You should check SQL Window functions post next.
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