String Functions
These scalar functions perform an operation on a string input value and return a string or numeric value.
| ASCII | NCHAR | SOUNDEX |
| CHAR | PATINDEX | SPACE |
| CHARINDEX | REPLACE | STR |
| DIFFERENCE | QUOTENAME | STUFF |
| LEFT | REPLICATE | SUBSTRING |
| LEN | REVERSE | UNICODE |
| LOWER | RIGHT | UPPER |
| LTRIM | RTRIM |
All built-in string functions, except for CHARINDEX and PATINDEX, are deterministic. They return the same value any time they are called with a given set of input values. For more information about function determinism, see Deterministic and Nondeterministic Functions.