在SQL Server中将Base 31的值转换为BigInt

Question

在我们的数据库中，我们使用主键作为数字0到9以及字母表中所有不是誓言的字母的组合。包括字母Y. 我创建了这个表来组织它。

CREATE Table Base31 
(ID varchar(1), 
NumberValue bigint) 

GO 

Insert into Base31 SELECT '0', '0' 
Insert into Base31 SELECT '1', '1' 
Insert into Base31 SELECT '2', '2' 
Insert into Base31 SELECT '3', '3' 
Insert into Base31 SELECT '4', '4' 
Insert into Base31 SELECT '5', '5' 
Insert into Base31 SELECT '6', '6' 
Insert into Base31 SELECT '7', '7' 
Insert into Base31 SELECT '8', '8' 
Insert into Base31 SELECT '9', '9' 
Insert into Base31 SELECT 'B', '10' 
Insert into Base31 SELECT 'C', '11' 
Insert into Base31 SELECT 'D', '12' 
Insert into Base31 SELECT 'F', '13' 
Insert into Base31 SELECT 'G', '14' 
Insert into Base31 SELECT 'H', '15' 
Insert into Base31 SELECT 'J', '16' 
Insert into Base31 SELECT 'K', '17' 
Insert into Base31 SELECT 'L', '18' 
Insert into Base31 SELECT 'M', '19' 
Insert into Base31 SELECT 'N', '20' 
Insert into Base31 SELECT 'P', '21' 
Insert into Base31 SELECT 'Q', '22' 
Insert into Base31 SELECT 'R', '23' 
Insert into Base31 SELECT 'S', '24' 
Insert into Base31 SELECT 'T', '25' 
Insert into Base31 SELECT 'V', '26' 
Insert into Base31 SELECT 'W', '27' 
Insert into Base31 SELECT 'X', '28' 
Insert into Base31 SELECT 'Y', '29' 
Insert into Base31 SELECT 'Z', '30' 

我想将这些主键转换为数字值，但我一直运行int int限制。我已经改变了所有使用大的int数据类型。我怎样才能让算法使用大的int数据类型？

GO 
CREATE Proc Base_31 @v varchar(8) 

as  

DECLARE @Ai bigint 
DECLARE @Bi bigint 
DECLARE @Ci bigint 
DECLARE @Di bigint 
DECLARE @Ei bigint 
DECLARE @Fi bigint 
DECLARE @Gi bigint 
DECLARE @Hi bigint 

SELECT @Ai = NumberValue     from Base31 where  RIGHT(@v,1) = ID 
SELECT @Bi = (NumberValue * POWER(31,1)) from Base31 where LEFT(RIGHT(@v,2),1) = ID 
SELECT @Ci = (NumberValue * POWER(31,2)) from Base31 where LEFT(RIGHT(@v,3),1) = ID 
SELECT @Di = (NumberValue * POWER(31,3)) from Base31 where LEFT(RIGHT(@v,4),1) = ID 
SELECT @Ei = (NumberValue * POWER(31,4)) from Base31 where LEFT(RIGHT(@v,5),1) = ID 
SELECT @Fi = (NumberValue * POWER(31,5)) from Base31 where LEFT(RIGHT(@v,6),1) = ID 
SELECT @Gi = (NumberValue * POWER(31,6)) from Base31 where LEFT(RIGHT(@v,7),1) = ID 
SELECT @Hi = (NumberValue * POWER(31,7)) from Base31 where LEFT(  @v ,1) = ID 

SELECT @v  AS Original 
    , Cast(@Ai AS bigint) 
    + Cast(@Bi AS bigint) 
    + Cast(@Ci AS bigint) 
    + Cast(@Di AS bigint) 
    + Cast(@Ei AS bigint) 
    + Cast(@Fi AS bigint) 
    + Cast(@Gi AS bigint) 
    + Cast(@Hi AS bigint) 
    as [Base 31 converted] 
GO 

Answer 1

问题是POWER函数返回与第一个参数相同的类型。所以你只需要明确地将第一个参数投给bigint。

该语句将失败：

select power(31,7) 

而这其中的工作原理：

select power(cast(31 as bigint),7) 

Answer 2

有一个更好的方式来做到这一点。下面的方法适用于任意长度的数字和任意的基数，只需稍作调整：

-- First convert a bigint to base-31 number string. 
DECLARE @number bigint 

SET @number = 123740194325432 

DECLARE @Base31 table 
(Digit varchar(1) NOT NULL, 
Value bigint NOT NULL PRIMARY KEY) 

INSERT into @Base31 (Digit, Value) VALUES ('0', '0') 
INSERT into @Base31 (Digit, Value) VALUES ('1', '1') 
INSERT into @Base31 (Digit, Value) VALUES ('2', '2') 
INSERT into @Base31 (Digit, Value) VALUES ('3', '3') 
INSERT into @Base31 (Digit, Value) VALUES ('4', '4') 
INSERT into @Base31 (Digit, Value) VALUES ('5', '5') 
INSERT into @Base31 (Digit, Value) VALUES ('6', '6') 
INSERT into @Base31 (Digit, Value) VALUES ('7', '7') 
INSERT into @Base31 (Digit, Value) VALUES ('8', '8') 
INSERT into @Base31 (Digit, Value) VALUES ('9', '9') 
INSERT into @Base31 (Digit, Value) VALUES ('B', '10') 
INSERT into @Base31 (Digit, Value) VALUES ('C', '11') 
INSERT into @Base31 (Digit, Value) VALUES ('D', '12') 
INSERT into @Base31 (Digit, Value) VALUES ('F', '13') 
INSERT into @Base31 (Digit, Value) VALUES ('G', '14') 
INSERT into @Base31 (Digit, Value) VALUES ('H', '15') 
INSERT into @Base31 (Digit, Value) VALUES ('J', '16') 
INSERT into @Base31 (Digit, Value) VALUES ('K', '17') 
INSERT into @Base31 (Digit, Value) VALUES ('L', '18') 
INSERT into @Base31 (Digit, Value) VALUES ('M', '19') 
INSERT into @Base31 (Digit, Value) VALUES ('N', '20') 
INSERT into @Base31 (Digit, Value) VALUES ('P', '21') 
INSERT into @Base31 (Digit, Value) VALUES ('Q', '22') 
INSERT into @Base31 (Digit, Value) VALUES ('R', '23') 
INSERT into @Base31 (Digit, Value) VALUES ('S', '24') 
INSERT into @Base31 (Digit, Value) VALUES ('T', '25') 
INSERT into @Base31 (Digit, Value) VALUES ('V', '26') 
INSERT into @Base31 (Digit, Value) VALUES ('W', '27') 
INSERT into @Base31 (Digit, Value) VALUES ('X', '28') 
INSERT into @Base31 (Digit, Value) VALUES ('Y', '29') 
INSERT into @Base31 (Digit, Value) VALUES ('Z', '30') 

DECLARE @base bigint 
DECLARE @power bigint 
DECLARE @divisor bigint 
DECLARE @output varchar(50) 
DECLARE @digit varchar(1) 
DECLARE @digitValue bigint 

SET @output = '' 
SET @base = 31 

IF @number < 0 
BEGIN 
    SET @number = ABS(@number) 
    SET @output = '-' 
END 

IF NOT @number = 0 
BEGIN 
    /* Due to the fact that the LOG10 function in SQL yields a float which limits the 
    available precision of the logarithm, numbers above 147209586032873 may have some 
    artifacts, i.e. LOG10(147209586032874) = LOG10(147209586032873). In actual practice, 
    I've found that numbers above 31^10 - 5 may manifest a leading zero when they are 
    near a power of 31, i.e. numbers in the ranges 31^10 - 4 to 31^10 - 1 and 
    31^11 - 158 to 31^11 - 1. */ 

    SET @power = FLOOR(LOG10(@number)/LOG10(@base)) 
END 

WHILE @power >= 0 AND @number > 0 
BEGIN 
    SET @divisor = POWER(@base, @power) 
    SET @digitValue = @number/@divisor 
    SET @number = @number % @divisor 

    SELECT @digit = Digit 
    FROM @Base31 
    WHERE Value = @digitValue 

    SELECT @output = @output + @digit 
    SET @power = @power - 1 
END 

SET @output = @output + COALESCE(REPLICATE('0', @power + 1), '0') 

SELECT @output 

-- Now convert the base-31 number string back to a bigint and see if we're right. 
DECLARE @position bigint 

SET @position = LEN(@output) 
SET @number = 0 

WHILE @position > 0 
BEGIN 
    SET @digit = SUBSTRING(@output, @position, 1) 

    SELECT @digitValue = Value 
    FROM @base31 
    WHERE Digit = @digit 

    SET @power = LEN(@output) - @position 
    SET @number = @number + (@digitValue * POWER(@base, @power)) 
    SET @position = @position - 1 
END 

SELECT @number