SQL Server basic functions-string functions

Length and Analysis

Datalength (char_expr) returns the number of characters in the string, but does not contain spaces

Substring (expression, start, length ).

Right (char_expr, int_expr) returns int_expr characters to the right of the string

Character operation class

Convert upper (char_expr) to uppercase

Lower (char_expr) to lowercase

Space (int_expr) generates int_expr Spaces

Replicate (char_expr, int_expr) copies the string int_expr times

Reverse (char_expr) reverse string

Stuff (char_expr1, start, length, char_expr2)

The length starting with start is replaced by char_expr2.

Ltrim (char_expr) rtrim (char_expr) removes Spaces

The ASCII (char) Char (ASCII) function corresponds to each other, and the ASCII code is used.

String search

Charindex (char_expr, expression) returns the starting position of char_expr

Patindex ("% pattern %", expression) returns the starting position of the specified mode. Otherwise, it is 0.