Define Function

CREATE OR ALTER FUNCTION ufn_IsWordComprised(@setOfLetters VARCHAR(20), @word VARCHAR(20))
RETURNS BIT
AS
BEGIN
    DECLARE @i INT = 1;
    DECLARE @Checker BIT = 0;

    WHILE @i <= LEN(@word)
    BEGIN
        DECLARE @SetLetter CHAR(1) = SUBSTRING(@word, @i, 1);

        DECLARE @j INT = 1;

        WHILE @j <= LEN(@setOfLetters)
        BEGIN
            DECLARE @WordLetter CHAR(1) = SUBSTRING(@setOfLetters, @j, 1);

            IF @SetLetter = @WordLetter
            BEGIN
                SET @Checker = 1;
                BREAK;
            END
            SET @j += 1;
            SET @Checker = 0;
        END

        IF(@Checker = 0)
            RETURN 0;
        SET @i +=1;
    END

    RETURN 1;
END