SQL in a Nutshell, 3rd Edition

String Functions and Operators

Basic string functions and operators offer a number of capabilities and return string values as their results. Some string functions are dyadic, indicating that they operate on two strings at once. ANSI SQL supports the string functions listed in Table 4-9.

Table 4-9. SQL string functions and operators

Function or operator	Usage
Concatenation operator	Appends two or more literal string expressions, column values, or variables together into one string
CONVERT	Converts a string to a different representation within the same character set
LOWER	Converts a string to all lowercase characters
OVERLAY	Returns the result of replacing a substring of one string with another
SUBSTRING	Returns a portion of a string
TRANSLATE	Converts a string from one character set to another
TRIM	Removes leading characters, trailing characters, or both from a character string
UPPER	Converts a string to all uppercase characters