SQL string Functions

The string functions are shown in the following table:

Function	Parameters	Function
+	(expression,expression)	Connect two or more strings, binary strings, column names
Ascⅱ	(char_expr)	Returns the Ascⅱ value of the leftmost character in an expression
CHAR	(integer_expr)	Returns the character corresponding to the Ascⅱ value represented by an integer
LOWER	(char_expr)	Convert uppercase characters to lowercase characters
UPPER	(char_expr)	Convert lowercase characters to uppercase characters
LTRIM	(char_expr)	Delete a space at the beginning of a string
RTRIM	(char_expr)	Remove the trailing space of a string
Right	(char_expr,integer_expr)	Returns a partial string after integer_expr characters in a char_expr string, and returns NULL when the integer_expr is negative
MySpace	(integer_expr)	Returns a string consisting of spaces that are equal to integer_expr values and integer_expr to NULL when negative
Str	(Float_expr[,length[,decimal]])	Converts a numeric data to a string, length as a string, and decimal as the number of decimal places
STUFF	(CHAR_EXPR1,START,LENGTH,CHAR_EXPR2)	Deletes the length character from the start character position of the CHAR_EXPR1 character and inserts the CHAR_EXPR2 string into the start of the CHAR_EXPR1
SUBSTRING	(expression,start,length)	Returns the length character from the first word entered prompt of the expression
REVERSE	(char_expr)	Returns the reverse order of char_expr
CHARINDEX	(' pattern ', expression)	Returns the starting position of the specified pattern string in an expression
Difference	(CHAR_EXPR1,CHAR_EXPR2)	Compares two strings, returns their similarity, and returns a value of 1~4
PATINDEX	('%prattern% ', expression)	Returns the starting position for the first occurrence of pattern in expression
REPLICATE	(char_expr,integer_expr)	Returns a string that is repeated integer_expr by char_expr
SOUNDEX	(char_expr)	Returns a four-code description of the similarity of the string pronunciation