Return the database user name (will return the current user since no id is specified):
SELECT USER_NAME();
The USER_NAME() function returns the database user name based on the specified id.
If no id is specified, this function will return the name of the current user.
USER_NAME(id_number)
Return the login name information for the current user:
SELECT SYSTEM_USER;
The SYSTEM_USER function returns the login name for the current user.
SYSTEM_USER
Return the session settings for a specified option:
SELECT SESSIONPROPERTY('ANSI_NULLS');
The SESSIONPROPERTY() function returns the session settings for a specified option.
SESSIONPROPERTY(option)
Return the user name of the current user:
SELECT SESSION_USER;
The SESSION_USER function returns the name of the current user in the SQL Server database.
SESSION_USER
Compare two expressions:
SELECT NULLIF(25, 25);
The NULLIF() function returns NULL if two expressions are equal, otherwise it returns the first expression.
NULLIF(expr1, expr2)
Tests whether the expression is numeric:
SELECT ISNUMERIC(4567);
The ISNUMERIC() function tests whether an expression is numeric.
This function returns 1 if the expression is numeric, otherwise it returns 0.
ISNUMERIC(expression)
Return the specified value IF the expression is NULL, otherwise return the expression:
SELECT ISNULL(NULL, 'iampsp.com');
The ISNULL() function returns a specified value if the expression is NULL.
If the expression is NOT NULL, this function returns the expression.
ISNULL(expression, value)
Return “YES” if the condition is TRUE, or “NO” if the condition is FALSE:
SELECT IIF(500<1000, 'YES', 'NO');
The IIF() function returns a value if a condition is TRUE, or another value if a condition is FALSE.
IIF(condition, value_if_true, value_if_false)
Return the name of the current user in the SQL Server database:
SELECT CURRENT_USER;
The CURRENT_USER function returns the name of the current user in the SQL Server database.
CURRENT_USER
Convert an expression to int:
SELECT CONVERT(int, 25.65);
The CONVERT() function converts a value (of any type) into a specified datatype.
Tip: Also look at the CAST() function.
CONVERT(data_type(length), expression, style)