ASCII -- Returns the equivalent ASCII value for a specific character. CHAR_LENGTH -- Returns the character length of a string. CHARACTER_LENGTH -- Same as CHAR_LENGTH. CONCAT -- Adds expressions together, with a minimum of 2. CONCAT_WS -- Adds expressions together, but with a separator between each value. FIELD -- Returns an index value relative to the position of a value within a list of values. FIND IN SET -- Returns the position of a string in a list of strings. FORMAT -- When passed a number, returns that number formatted to include commas (eg 3,400,000). INSERT -- Allows you to insert one string into another at a certain point, for a certain number of characters. INSTR -- Returns the position of the first time one string appears within another. LCASE -- Converts a string to lowercase. LEFT -- Starting from the left, extracts the given number of characters from a string and returns them as another. LENGTH -- Returns the length of a string, but in bytes. LOCATE -- Returns the first occurrence of one string within another, LOWER -- Same as LCASE. LPAD -- Left pads one string with another, to a specific length. LTRIM -- Removes any leading spaces from the given string. MID -- Extracts one string from another, starting from any position. POSITION -- Returns the position of the first time one substring appears within another. REPEAT -- Allows you to repeat a string REPLACE -- Allows you to replace any instances of a substring within a string, with a new substring. REVERSE -- Reverses the string. RIGHT -- Starting from the right, extracts the given number of characters from a string and returns them as another. RPAD -- Right pads one string with another, to a specific length. RTRIM -- Removes any trailing spaces from the given string. SPACE -- Returns a string full of spaces equal to the amount you pass it. STRCMP -- Compares 2 strings for differences SUBSTR -- Extracts one substring from another, starting from any position. SUBSTRING -- Same as SUBSTR SUBSTRING_INDEX -- Returns a substring from a string before the passed substring is found the number of times equals to the passed number. TRIM -- Removes trailing and leading spaces from the given string. Same as if you were to run LTRIM and RTRIM together. UCASE -- Converts a string to uppercase. UPPER -- Same as UCASE.