SQL Server has many built-in functions.
This reference contains string, numeric, date,  
conversion, and some advanced functions 
in SQL Server.
| Function | 
Description | 
| ASCII | 
Returns the ASCII value for the specific character | 
| CHAR | 
Returns the character based on the ASCII code | 
| CHARINDEX | 
Returns the position of a substring in a string | 
| CONCAT | 
Adds two or more strings together | 
| Concat with + | 
Adds two or more strings together | 
| CONCAT_WS | 
Adds two or more strings together with a separator | 
| DATALENGTH | 
Returns the number of bytes used to represent an expression | 
| DIFFERENCE | 
Compares two SOUNDEX values, and returns an integer value | 
| FORMAT | 
Formats a value with the specified format | 
| LEFT | 
Extracts a number of characters from a string (starting from left) | 
| LEN | 
Returns the length of a string | 
| LOWER | 
Converts a string to lower-case | 
| LTRIM | 
Removes leading spaces from a string | 
| NCHAR | 
Returns the Unicode character based on the number code | 
| PATINDEX | 
Returns the position of a pattern in a string | 
| QUOTENAME | 
Returns a Unicode string with delimiters added to make the string 
a valid SQL Server delimited identifier | 
| REPLACE | 
Replaces all occurrences of a substring within a string, with a new 
substring | 
| REPLICATE | 
Repeats a string a specified number of times | 
| REVERSE | 
Reverses a string and returns the result | 
| RIGHT | 
Extracts a number of characters from a string (starting from right) | 
| RTRIM | 
Removes trailing spaces from a string | 
| SOUNDEX | 
Returns a four-character code to evaluate the similarity of two strings | 
| SPACE | 
Returns a string of the specified number of space characters | 
| STR | 
Returns a number as string | 
| STUFF | 
Deletes a part of a string and then inserts another part into the string, 
starting at a specified position | 
| SUBSTRING | 
Extracts some characters from a string | 
| TRANSLATE | 
Returns the string from the first argument after the characters specified in 
the second argument are translated into the characters specified in the third 
argument. | 
| TRIM | 
Removes leading and trailing spaces (or other specified characters) from a string | 
| UNICODE | 
Returns the Unicode value for the first 
character of the input expression | 
| UPPER | 
Converts a string to upper-case | 
| Function | 
Description | 
| ABS | 
Returns the absolute value of a number | 
| ACOS | 
Returns the arc cosine of a number | 
| ASIN | 
Returns the arc sine of a number | 
| ATAN | 
Returns the arc tangent of a number | 
| ATN2 | 
Returns the arc tangent of two numbers | 
| AVG | 
Returns the average value of an expression | 
| CEILING | 
Returns the smallest integer value that is >= a number | 
| COUNT | 
Returns the number of records returned by a select query | 
| COS | 
Returns the cosine of a number | 
| COT | 
Returns the cotangent of a number | 
| DEGREES | 
Converts a value in radians to degrees | 
| EXP | 
Returns e raised to the power of a specified number | 
| FLOOR | 
Returns the largest integer value that is <= to a number | 
| LOG | 
Returns the natural logarithm of a number, or the logarithm of a number to a 
specified base | 
| LOG10 | 
Returns the natural logarithm of a number to base 10 | 
| MAX | 
Returns the maximum value in a set of values | 
| MIN | 
Returns the minimum value in a set of values | 
| PI | 
Returns the value of PI | 
| POWER | 
Returns the value of a number raised to the power of another number | 
| RADIANS | 
Converts a degree value into radians | 
| RAND | 
Returns a random number | 
| ROUND | 
Rounds a number to a specified number of decimal places | 
| SIGN | 
Returns the sign of a number | 
| SIN | 
Returns the sine of a number | 
| SQRT | 
Returns the square root of a number | 
| SQUARE | 
Returns the square of a number | 
| SUM | 
Calculates the sum of a set of values | 
| TAN | 
Returns the tangent of a number | 
| Function | 
Description | 
| CURRENT_TIMESTAMP | 
Returns the current date and time | 
| DATEADD | 
Adds a time/date interval to a date and then returns the date | 
| DATEDIFF | 
Returns the difference between two dates | 
| DATEFROMPARTS | 
Returns a date from the specified parts (year, month, and day values) | 
| DATENAME | 
Returns a specified part of a date (as string) | 
| DATEPART | 
Returns a specified part of a date (as integer) | 
| DAY | 
Returns the day of the month for a specified date | 
| GETDATE | 
Returns the current database system date and time | 
| GETUTCDATE | 
Returns the current database system UTC date and time | 
| ISDATE | 
Checks an expression and returns 1 if it is a valid date, otherwise 0 | 
| MONTH | 
Returns the month part for a specified date (a number from 1 to 12) | 
| SYSDATETIME | 
Returns the date and time of the SQL Server | 
| YEAR | 
Returns the year part for a specified date | 
| Function | 
Description | 
  
| CAST | 
Converts a value (of any type) into a specified datatype | 
  
| COALESCE | 
Returns the first non-null value in a list | 
  
| CONVERT | 
Converts a value (of any type) into a specified datatype | 
  
| CURRENT_USER | 
Returns the name of the current user in the SQL Server database | 
| IIF | 
Returns a value if a condition is TRUE, or another value if a condition is FALSE | 
| ISNULL | 
Return a specified value if the expression is NULL, otherwise return the 
expression | 
| ISNUMERIC | 
Tests whether an expression is numeric | 
| NULLIF | 
Returns NULL if two expressions are equal | 
| SESSION_USER | 
Returns the name of the current user in the SQL Server database | 
| SESSIONPROPERTY | 
Returns the session settings for a specified option | 
| SYSTEM_USER | 
Returns the login name for the current user | 
| USER_NAME | 
Returns the database user name based on the specified id |