Text and image functions operate on text and image data. The text and image functions are:
Text and image built-in function names are not keywords. Use the set textsize option to limit the amount of text or image data that is retrieved by a select statement.
The patindex text function can be used on text and image columns and can also be considered a text and image function.
Use the datalength function to get the length of data in text and image columns.
text and image columns cannot be used:
As parameters to stored procedures
As values passed to stored procedures
As local variables
In order by, compute, and group by clauses
In an index
In a where clause, except with the keyword like