SET NOCOUNT ON

– Initialize some variables
DECLARE    @UpperCase VARCHAR(26),
    @LowerCase VARCHAR(26),
    @Numbers VARCHAR(10),
    @Special VARCHAR(13),
    @Temp VARCHAR(8000),
    @Password VARCHAR(8000),
    @i SMALLINT,
    @c VARCHAR(1),
    @v TINYINT

– Set the default items in each group of characters
SELECT    @UpperCase = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
    @LowerCase = 'abcdefghijklmnopqrstuvwxyz',
    @Numbers = '0123456789',
    @Special = '!@#$%&*()_+-=',
    @Temp = '',
    @Password = ''

– Enforce some limits on the length of the password
IF @UpperCaseItems > 20
    SET @UpperCaseItems = 20

IF @UpperCaseItems < -20
    SET @UpperCaseItems = -20

IF @LowerCaseItems > 20
    SET @LowerCaseItems = 20

IF @LowerCaseItems < -20
    SET @LowerCaseItems = -20

IF @NumberItems > 20
    SET @NumberItems = 20

IF @NumberItems < -20
    SET @NumberItems = -20

IF @SpecialItems > 20
    SET @SpecialItems = 20

IF @SpecialItems < -20
    SET @SpecialItems = -20

– Get the Upper Case Items
SET    @i = ABS(@UpperCaseItems)

WHILE @i > 0 AND LEN(@UpperCase) > 0
    SELECT    @v = ABS(CAST(CAST(NEWID() AS BINARY(16)) AS BIGINT)) % LEN(@UpperCase) + 1,
        @c = SUBSTRING(@UpperCase, @v, 1),
        @UpperCase =    CASE
                    WHEN @UpperCaseItems < 0 THEN STUFF(@UpperCase, @v, 1, '')
                    ELSE @UpperCase
                END,
        @Temp = @Temp + @c,
        @i = @i - 1

– Get the Lower Case Items
SET    @i = ABS(@LowerCaseItems)

WHILE @i > 0 AND LEN(@LowerCase) > 0   
    SELECT    @v = ABS(CAST(CAST(NEWID() AS BINARY(16)) AS BIGINT)) % LEN(@LowerCase) + 1,
        @c = SUBSTRING(@LowerCase, @v, 1),
        @LowerCase =    CASE
                    WHEN @LowerCaseItems < 0 THEN STUFF(@LowerCase, @v, 1, '')
                    ELSE @LowerCase
                END,
        @Temp = @Temp + @c,
        @i = @i - 1

– Get the Number Items
SET    @i = ABS(@NumberItems)

WHILE @i > 0 AND LEN(@Numbers) > 0   
    SELECT    @v = ABS(CAST(CAST(NEWID() AS BINARY(16)) AS BIGINT)) % LEN(@Numbers) + 1,
        @c = SUBSTRING(@Numbers, @v, 1),
        @Numbers =    CASE
                    WHEN @NumberItems < 0 THEN STUFF(@Numbers, @v, 1, '')
                    ELSE @Numbers
                END,
        @Temp = @Temp + @c,
        @i = @i - 1

– Get the Special Items
SET    @i = ABS(@SpecialItems)

WHILE @i > 0 AND LEN(@Special) > 0   
    SELECT    @v = ABS(CAST(CAST(NEWID() AS BINARY(16)) AS BIGINT)) % LEN(@Special) + 1,
        @c = SUBSTRING(@Special, @v, 1),
        @Special =    CASE
                    WHEN @SpecialItems < 0 THEN STUFF(@Special, @v, 1, '')
                    ELSE @Special
                END,
        @Temp = @Temp + @c,
        @i = @i - 1

– Scramble the order of the selected items
WHILE LEN(@Temp) > 0   
    SELECT    @v = ABS(CAST(CAST(NEWID() AS BINARY(16)) AS BIGINT)) % LEN(@Temp) + 1,
        @Password = @Password + SUBSTRING(@Temp, @v, 1),
        @Temp = STUFF(@Temp, @v, 1, '')

SELECT    @Password