What is the usage of Oracle’s WM_CONCAT function?

The WM_CONCAT function is an aggregate function in the Oracle database that is used to combine multiple rows of data into a single string with a specified delimiter. Its syntax format is as follows:

Concatenate the values of a specific expression.

In this case, expression refers to the column or expression that needs to be linked.

With the WM_CONCAT function, multiple rows of data can be concatenated into a single string. For example:

List employees as employee_list using WM_CONCAT function.

The statement above will return a string containing the names of all employees, separated by commas.

It is important to note that the WM_CONCAT function is an internal function in Oracle 11g and earlier versions, not officially supported, and has been removed in Oracle 12c and later versions. To achieve the same functionality, you can use the LISTAGG function as a replacement for the WM_CONCAT function.