What does nvl in oracle mean?

Oracle's NVL function is used to handle NULL values ​​and has two parameters: expression and replacement value. If the expression is NULL, the replacement value is returned, otherwise the expression is returned. Uses include preventing errors, filling null values, and providing consistency.

NVL function in Oracle

The NVL function is used in Oracle to handle NULL values. It takes two Parameters:

• Expression to check (may be NULL)
• Replacement value returned if expression is NULL

Syntax:

<code>NVL(expr, replace_value)</code>

How it works:

The NVL function checks the first parameter and if it is NULL, returns the second parameter (replacement value) . Otherwise, it returns the first parameter.

Example:

<code>SELECT NVL(column_name, 0) FROM table_name;</code>

This query returns the value in the column_name column, or 0 if the value is empty.

Purpose:

The NVL functions can be used to prevent errors or inconsistencies caused by NULL values. It can also be used to fill in null values ​​for calculation or analysis.

Other notes:

• The replacement value can be any valid data type, but it must be compatible with the data type of the first parameter.
• If the first argument is not NULL, the NVL function does not evaluate the replacement value.
• The NVL function is typically used to handle NULL values ​​in a single column. For handling multiple NULL values ​​or complex conditions, you can use CASE expressions.

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