Codewars Kata SQL
Your task is to add up letters to one letter.
In SQL, you will be given a table
letters, with a string column
letter. Return the sum of the letters in a column
- Letters will always be lowercase.
- Letters can overflow (see second to last example of the description)
- If no letters are given, the function should return
table(letter: ["a", "b", "c"]) = "f"
table(letter: ["a", "b"]) = "c"
table(letter: ["z"]) = "z"
table(letter: ["z", "a"]) = "a"
table(letter: ["y", "c", "b"]) = "d" -- notice the letters overflowing
table(letter: ) = "z"
Confused? Start by converting the letters to numbers: a => 1, b => 2, etc. Add them up. Think about the overflow yourself. Once that’s done, convert it back to a letter.
- The SQL CHR function accepts an ASCII code and returns the corresponding character.
- The COALESCE function in SQL server is used to return the first Non-NULL value from the list of columns/arguments given in order.
- COALESCE is considered similar to writing a CASE statement expression in SQL.
SELECT COALESCE(CHR(CAST((SUM(ascii(letter) - 96)-1)%26 as int)+97), 'z')