SQL Server String function quick query

SQL Server String functions are listed in different categories for easy access and memory. I believe everyone has a deep programming Foundation in other aspects. Literally, everyone knows the meaning of these functions, I have not explained these functions too much. I will focus on some experiences. For more information, see books online.

ASCII (character_expression)Returns the ASCII of the leftmost character.CodeValue
Char (integer_expression)

Unicode (ncharacter_expression)Returns the integer of the first character of the input expression, as defined in the Unicode standard.
Nchar (integer_expression)

Lower (character_expression)Returns the string in lowercase.
Upper (character_expression)

Ltrim (character_expression)Truncates left-side spaces.
Rtrim (character_expression)

Len (string_expression)Returns the number of characters (not bytes), excluding trailing spaces.
Left (character_expression, integer_expression)Trailing spaces may also be returned.
Right (character_expression, integer_expression)
Substring (expression, start, length)The first character is at 1.

Charindex (expression1, expression2 [, start_location])Position of expression1 in expression2. if no value is found, 0 is returned.
Patindex (% pattern %, expression)Pattern should have wildcards, like
Reverse (character_expression)Reverse string
Replace (string_expression, string_expression2, string_expression3)Replace the second expression in the first expression with the third expression
Stuff (character_expression, start, length, character_expression)Press Start and length to delete the content of the first expression and insert the fourth expression at the start position.

Replication (character_expression, integer_expression)Duplicate string
Space (integer_expression)Repeat integer_expression with spaces

Soundex (character_expression)Returns a specific string of four lengths Based on the string.
Difference (character_expression, character_expression)Compare the return values of the two expressions in sounex with several different characters. The return value is [0-4].

STR (float_expression [, length [, decimal]) returns the string value converted from a number.
quotename (character_string [, quote_character]) returns the Unicode string with a separator.