Functions are called to perform a calculation and return a value. Functions must be invoked with no space between the function name and the parenthesis following it:
NOW() Correct NOW () Incorrect
If you pass multiple arguments to a function, arguments must be separated by commas. Spaces are allowed around function arguments:
CONCAT("abc","def") This is okay CONCAT( "abc" , "def") This is okay, too
GREATEST( expr1,expr2,… )
Returns the largest argument, where "largest" is defined according to the following rules:
If the function is called in an integer context or all the arguments are integers, the arguments are compared as integers.
If the function is called in a floating-point context or all the arguments ...