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# String Functions (Transact-SQL)
[!INCLUDE[tsql-appliesto-ss2008-all-md](../../includes/tsql-appliesto-ss2008-all-md.md)]

  The following scalar functions perform an operation on a string input value and return a string or numeric value:  
  
||||  
|-|-|-| 
|[ASCII](../../t-sql/functions/ascii-transact-sql.md)|[CHAR](../../t-sql/functions/char-transact-sql.md)|[CHARINDEX](../../t-sql/functions/charindex-transact-sql.md)|
|[CONCAT](../../t-sql/functions/concat-transact-sql.md)|[CONCAT_WS](../../t-sql/functions/concat-ws-transact-sql.md)|[DIFFERENCE](../../t-sql/functions/difference-transact-sql.md) |
|[FORMAT](../../t-sql/functions/format-transact-sql.md)|[LEFT](../../t-sql/functions/left-transact-sql.md)|[LEN](../../t-sql/functions/len-transact-sql.md) |
|[LOWER](../../t-sql/functions/lower-transact-sql.md)|[LTRIM](../../t-sql/functions/ltrim-transact-sql.md)|[NCHAR](../../t-sql/functions/nchar-transact-sql.md) |
|[PATINDEX](../../t-sql/functions/patindex-transact-sql.md)|[QUOTENAME](../../t-sql/functions/quotename-transact-sql.md)|[REPLACE](../../t-sql/functions/replace-transact-sql.md) |
|[REPLICATE](../../t-sql/functions/replicate-transact-sql.md)|[REVERSE](../../t-sql/functions/reverse-transact-sql.md) |[RIGHT](../../t-sql/functions/right-transact-sql.md) |
|[RTRIM](../../t-sql/functions/rtrim-transact-sql.md)|[SOUNDEX](../../t-sql/functions/soundex-transact-sql.md) |[SPACE](../../t-sql/functions/space-transact-sql.md) |
|[STR](../../t-sql/functions/str-transact-sql.md)|[STRING_AGG](../../t-sql/functions/string-agg-transact-sql.md)|[STRING_ESCAPE](../../t-sql/functions/string-escape-transact-sql.md) |
|[STRING_SPLIT](../../t-sql/functions/string-split-transact-sql.md)|[STUFF](../../t-sql/functions/stuff-transact-sql.md)|[SUBSTRING](../../t-sql/functions/substring-transact-sql.md) |
|[TRANSLATE](../../t-sql/functions/translate-transact-sql.md)|[TRIM](../../t-sql/functions/trim-transact-sql.md)|[UNICODE](../../t-sql/functions/unicode-transact-sql.md) |
|[UPPER](../../t-sql/functions/upper-transact-sql.md) | | |


  
 All built-in string functions except `FORMAT` are deterministic. This means they return the same value any time they are called with a specific set of input values. For more information about function determinism, see [Deterministic and Nondeterministic Functions](../../relational-databases/user-defined-functions/deterministic-and-nondeterministic-functions.md).  
  
 When string functions are passed arguments that are not string values, the input type is implicitly converted to a text data type. For more information, see [Data Type Conversion (Database Engine)](../../t-sql/data-types/data-type-conversion-database-engine.md).  
  
## See Also  
 [Built-in Functions (Transact-SQL)](~/t-sql/functions/functions.md)