This is a quick reference list of SQL Server string functions and how they are used to work with databases.

• SQL – SQL Server ASCII() Function
  The SQL Server ASCII() function returns the ASCII value for the specified character.
• SQL – SQL Server CHAR() Function
  The SQL Server CHAR() function returns the character based on the ASCII code specified.
• SQL – SQL Server CHARINDEX() Function
  The SQL Server CHARINDEX() function searches for a substring in a string, and returns the position. If the substring is not found, this function returns 0.
• SQL – SQL Server CONCAT() Function
  The SQL Server CONCAT() function adds two or more strings together.
• SQL – SQL Server Concat With +
  The SQL Server + operator allows you to add two or more strings together.
• SQL – SQL Server CONCAT_WS() Function
  The SQL Server CONCAT_WS() function adds two or more strings together with a separator.
• SQL – SQL Server DATALENGTH() Function
  The SQL Server DATALENGTH() function returns the number of bytes used to represent an expression.
• SQL – SQL Server DIFFERENCE() Function
  The SQL Server DIFFERENCE() function compares two SOUNDEX values, and returns an integer.
• SQL – SQL Server FORMAT() Function
  The SQL Server FORMAT() function formats a value with the specified format (and an optional culture in SQL Server 2017).
• SQL – SQL Server LEFT() Function
  The SQL Server LEFT() function extracts a number of characters (starting from left) from a string.
• SQL – SQL Server LEN() Function
  The SQL Server LEN() function returns the length of a string. Trailing spaces (after) are not included, but leading spaces (before) are included.
• SQL – SQL Server LOWER() Function
  The SQL Server LOWER() function converts a string to lower-case.
• SQL – SQL Server LTRIM() Function
  The SQL Server LTRIM() function removes leading spaces from a string. Leading spaces are spaces before (left of) the string.
• SQL – SQL Server NCHAR() Function
  The SQL Server NCHAR() function returns the Unicode character based on the number code provided.
• SQL – SQL Server PATINDEX() Function
  The SQL Server PATINDEX() function returns the position of a pattern in a string. If the pattern is not found, this function returns 0.
• SQL – SQL Server QUOTENAME() Function
  The SQL Server QUOTENAME() function returns a Unicode string with delimiters added to make the string a valid SQL Server delimited identifier.
• SQL – SQL Server REPLACE() Function
  The SQL Server REPLACE() function replaces all occurrences of a substring (case-insensitive) within a string, with a new substring.
• SQL – SQL Server REPLICATE() Function
  The SQL Server REPLICATE() function repeats a specified string a specified number of times.
• SQL – SQL Server REVERSE() Function
  The SQL Server REVERSE() function reverses a specified string and returns the result.
• SQL – SQL Server RIGHT() Function
  The SQL Server RIGHT() function extracts a number of characters (starting from right) from a string.
• SQL – SQL Server RTRIM() Function
  The SQL Server RTRIM() function removes trailing spaces from a string. Trailing spaces are spaces after (right of) the string.
• SQL – SQL Server SOUNDEX() Function
  The SQL Server SOUNDEX() function returns a four-character code to evaluate the similarity of two expressions.
• SQL – SQL Server SPACE() Function
  The SQL Server SPACE() function returns a string of the specified number of space characters.
• SQL – SQL Server STR() Function
  The SQL Server STR() function returns a number as a string.
• SQL – SQL Server STUFF() Function
  The SQL Server STUFF() function deletes a part of a string, starting at a specified position, and then inserts a new part into the string at that position.
• SQL – SQL Server SUBSTRING() Function
  The SQL Server SUBSTRING() function extracts a specified number of characters from a specified position in a string.
• SQL – SQL Server TRANSLATE() Function
  The SQL Server TRANSLATE() function returns the string from the first argument after the characters in the second argument are translated into it.
• SQL – SQL Server TRIM() Function
  The SQL Server TRIM() function removes leading and trailing spaces (default) OR other specified characters from the start or end of a string.
• SQL – SQL Server UNICODE() Function
  The SQL Server UNICODE() function returns an integer value (the Unicode value) for the first character of the input expression.
• SQL – SQL Server UPPER() Function
  The SQL Server UPPER() function converts a string to upper-case.