The COMPRESS function is a scalar function and compresses the input variable, column, or expression using the GZIP algorithm. The function accepts an expression, which can be either string or binary, but again, the deprecated data types text, ntext, and image are not supported.
The return type of the function is VARBINARY(MAX).
Use this function with wide text columns, especially when you do not plan to query them often. For large strings, the compression rate can be significant, particularly when the original string is XML. Here is an example of significant compression. The example uses the output of the system Extended Event session system_health to check the compression rate when you use the COMPRESS function for the target_data ...
