SQL Server CheckSum 是否计算 CRC？如果不是，我怎样才能让 MS SQL 在任意 varchar 列上计算 CRC？答案

【问题标题】：Does SQL Server CheckSum calculate a CRC? If not how can I get MS SQL to calculate a CRC on an arbitrary varchar column?SQL Server CheckSum 是否计算 CRC？如果不是，我怎样才能让 MS SQL 在任意 varchar 列上计算 CRC？
【发布时间】：2013-06-30 11:24:07
【问题描述】：

SQL Server CheckSum 是否计算 CRC？如果不是，我怎样才能让 SQL Server 在任意 varchar 列上计算 CRC？

【问题讨论】：

标签： sql sql-server

【解决方案1】：

我对模型的粗鲁表示歉意，但这似乎可以进行正确的 CRC32 计算。我不是 TSQL 专家，我相信真正的 SQL Server 专业人士可以大大改善这一点......

@input 是计算 CRC32 的变量。将其打包为 sproc 或 udf 应该很简单，并且可以将查找表分解为永久表（甚至可以即时计算）。

无论如何，它似乎工作。我有兴趣看到任何改进，因为学习新技巧总是好的:)

编辑：我已经对照http://crc32-checksum.waraxe.us/ 检查了我的结果，目前看来还不错。

安德鲁

DECLARE @input VARCHAR(50)
SET @input = 'test'

SET NOCOUNT ON
DECLARE @tblLookup TABLE (ID INT IDENTITY(0,1) NOT NULL, Value BIGINT)
INSERT INTO @tblLookup VALUES (0)
INSERT INTO @tblLookup VALUES (1996959894)
INSERT INTO @tblLookup VALUES (3993919788)
INSERT INTO @tblLookup VALUES (2567524794)
INSERT INTO @tblLookup VALUES (124634137)
INSERT INTO @tblLookup VALUES (1886057615)
INSERT INTO @tblLookup VALUES (3915621685)
INSERT INTO @tblLookup VALUES (2657392035)
INSERT INTO @tblLookup VALUES (249268274)
INSERT INTO @tblLookup VALUES (2044508324)
INSERT INTO @tblLookup VALUES (3772115230)
INSERT INTO @tblLookup VALUES (2547177864)
INSERT INTO @tblLookup VALUES (162941995)
INSERT INTO @tblLookup VALUES (2125561021)
INSERT INTO @tblLookup VALUES (3887607047)
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DECLARE @crc BIGINT, @len INT, @i INT, @index INT
DECLARE @tblval BIGINT
SET @crc = 0xFFFFFFFF
SET @len = LEN(@input)
SET @i = 1

WHILE @i <= @len
BEGIN
    SET @index = ((@crc & 0xff) ^ ASCII(SUBSTRING(@input, @i, 1)))  
    SET @tblval = (SELECT Value FROM @tblLookup WHERE ID = @Index)
    SET @crc = (@crc / 256) ^ @tblval   
    SET @i = @i + 1 
END
SET @crc = ~@crc

SELECT @crc as CRC32, CONVERT(VARBINARY(4), @crc) as CRC32Hex

【讨论】：

我忘记输入编辑注释，但我在 TSQL 脚本的最后一行添加了“AS CRC32”，使其命名为选定的列。
我会明确地将索引值放入您的查找表中，而不是依赖 IDENTITY。由于表是本地的，因此您的方法应该 100% 的时间有效，但不能保证 IDENTITY 创建 seq 值。不过大多只是我的一个习惯。如果你知道值，不妨把它放进去
嗯...不知道。 TSQL 文档似乎另有说明：“IDENTITY [（种子，增量）] 种子：是用于加载到表中的第一行的值增量：是添加到前一个标识值的增量值已加载的行。"
@Andrew：如果插入回滚，插入的值将包含一个间隙。还有其他原因可能会导致出现差距，但没有一个真正适用于您的情况。就像我说的，在你的代码中你应该是安全的。当我出于习惯了解它们（包括递增#s）时，我会陈述它们。
@Andrew 请参阅 my answer 以获取缩短版本。

【解决方案2】：

我将 Andrew Rollings 的剧本缩短到 11 行，因此他确实得到了赞誉。这将在 SQL 2008 或更高版本中运行。如果在 DECLARE 之后设置变量值，它将在 SQL 2005 中运行。在 2005 年及以后，字符限制为 2048，在 SQL 2000 中，它类似于 512（我不记得在 SQL 中有多少 P 类型的 spt_value 2000）。但如有必要，可以对其进行修改。

DECLARE @input VARCHAR(50)
SET @input = 'test'

SET NOCOUNT ON
DECLARE
    @crc bigint = 0xFFFFFFFF,
    @Lookup varbinary(2048) = 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

SELECT @crc = (@crc / 256) ^ Substring(@Lookup, ((@crc & 0xFF) ^ Ascii(Substring(@input, V.Number, 1))) * 4 + 1, 4)
FROM master.dbo.spt_values V
WHERE V.type = 'P' AND V.number BETWEEN 1 AND Len(@input)

SET @crc = ~@crc;
SELECT @crc CRC32, Convert(VARBINARY(4), @crc) CRC32Hex;

【讨论】：

嗯，一些进一步的分析表明我应该检查 CRC 是否真的以正确的顺序计算。如果来自master.dbo.spt_values 的行顺序错误，则CRC 错误。

【解决方案3】：

对于任何需要这种函数形式的人，我从 Andrew Rollings 和 ErikE 那里得到了解决方案，并将其放入一组可用的函数中。我还在下面的函数 NCRC32 中提供了 Unicode 字符的解决方案：

CREATE FUNCTION dbo.IndexTable
(
      @FirstIndex           bigint
    , @LastIndex            bigint
)
RETURNS @Result table
(
    Id BIGINT PRIMARY KEY
)
WITH SCHEMABINDING
AS
/***************************************************************************************************
    DESCRIPTION:
         Create an one column table of indexes starting with first specified index and 
         ending with last specified index.

    INPUT PARAMETERS:
         @FirstIndex:    First index to start the list of indexes with.
         @LastIndex:     Last index to end the list of indexes with.

    RETURN VALUE:
         Table with list of specified indexes.

    EXAMPLES:
        SELECT * FROM dbo.IndexTable(1, 20)
        SELECT * FROM dbo.IndexTable(1, 16)
        SELECT * FROM dbo.IndexTable(1, 17)
        SELECT * FROM dbo.IndexTable(1, 18)
        SELECT * FROM dbo.IndexTable(1, 1)
        SELECT * FROM dbo.IndexTable(1, 0)
***************************************************************************************************/
BEGIN
    DECLARE @max        bigint
    ,       @offset     bigint
    ;
    IF @LastIndex IS NULL RETURN ;
    IF @FirstIndex IS NULL RETURN ;
    INSERT INTO @Result 
    VALUES  (@FirstIndex+0), (@FirstIndex+1), (@FirstIndex+2), (@FirstIndex+3), (@FirstIndex+4)
    ,       (@FirstIndex+5), (@FirstIndex+6), (@FirstIndex+7), (@FirstIndex+8), (@FirstIndex+9)
    ;
    SELECT @max= MAX(Id) FROM @Result
    ;
    WHILE @max < @LastIndex
    BEGIN
        SET @offset = (1 + @max - @FirstIndex)
        ;
        INSERT
        INTO    @Result
        SELECT  Id = Id + @offset
        FROM    @Result
        WHERE   Id <= (@LastIndex - @offset)
        ;
        SELECT @max= MAX(Id) FROM @Result
        ;
    END
    DELETE FROM @Result WHERE Id > @LastIndex
    ;
    RETURN
END
GO

CREATE FUNCTION dbo.CRC32calc
/***************************************************************************************************
    DESCRIPTION
        Add a byte value to a CRC calculation.

    INPUT PARAMETERS:
        @crc            Current CRC value.
        @byteval        Byte value to add to CRC value.

    RETURN VALUE:
        Resulting CRC with bytevalue added.

    USAGE:
        Used by functions dbo.CRC32 and dbo.NCRC32
***************************************************************************************************/
(
    @crc        bigint,
    @byteval    int
)
RETURNS bigint
WITH SCHEMABINDING
AS
BEGIN
    DECLARE @Lookup     varbinary(2048) = 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
    ;
    RETURN (@crc / 256) ^ Substring(@Lookup, ((@crc & 0xFF) ^ @byteval) * 4 + 1, 4)
    ;
END
GO

CREATE FUNCTION dbo.CRC32
/***************************************************************************************************
    DESCRIPTION
        Compute 32-bit CRC from an ASCII character array.

    INPUT PARAMETERS:
        @input          ASCII text to compute CRC for.

    RETURN VALUE:
        Resulting 32-bit CRC value.

    EXAMPLES:
        SELECT  t.input, csum = CHECKSUM(t.input), t.crc, crchex = CONVERT(VARBINARY(8), t.crc)
        FROM    (   SELECT  t.input, crc = dbo.CRC32(t.input)
                    FROM    (         SELECT  input = 'test'
                                UNION SELECT  input = 'x'
                                UNION SELECT  input = ''
                                UNION SELECT  input = NULL
                                UNION SELECT  input = 'stop'
                                UNION SELECT  input = 'pots'
                                UNION SELECT  input = 'System.IO.Stream'
                                UNION SELECT  input = 'SYSTEM.IO.Stream'
                                UNION SELECT  input = 'Test.fqn.data'
                                UNION SELECT  input = 'Test.fqn.datax'
                            ) AS t
                ) AS t
***************************************************************************************************/
(
    @input varchar(max)
)
RETURNS int
WITH SCHEMABINDING
AS
BEGIN
    DECLARE @crc        bigint = 0xFFFFFFFF
    ,       @result     int
    ;
    SELECT @crc = dbo.CRC32calc(@crc, Ascii(Substring(@input, v.id, 1)))
    FROM    dbo.IndexTable(1, LEN(@input)) AS v
    ORDER
    BY      v.Id
    ;
    SET @result = CONVERT(int, CONVERT(VARBINARY(4), ~@crc)) ;
    RETURN @result ;
END
GO

CREATE FUNCTION dbo.NCRC32
/***************************************************************************************************
    DESCRIPTION
        Compute 32-bit CRC from a UNICODE character array.

    INPUT PARAMETERS:
        @input          ASCII text to compute CRC for.

    RETURN VALUE:
        Resulting 32-bit CRC value.

    EXAMPLES:
        SELECT  t.input, csum = CHECKSUM(t.input), t.crc, crchex = CONVERT(VARBINARY(8), t.crc)
        FROM    (   SELECT  t.input, crc = dbo.NCRC32(t.input)
                    FROM    (         SELECT  input = N'test'
                                UNION SELECT  input = N'x'
                                UNION SELECT  input = N''
                                UNION SELECT  input = NULL
                                UNION SELECT  input = 'stop'
                                UNION SELECT  input = 'pots'
                                UNION SELECT  input = N'System.IO.Stream'
                                UNION SELECT  input = N'SYSTEM.IO.Stream'
                                UNION SELECT  input = N'Test.fqn.data'
                                UNION SELECT  input = N'Test.fqn.datax'
                            ) AS t
                ) AS t
***************************************************************************************************/
(
    @input nvarchar(max)
)
RETURNS int
WITH SCHEMABINDING
AS
BEGIN
    DECLARE @crc        bigint = 0xFFFFFFFF
    ,       @result     int
    ;
    SELECT  @crc = dbo.CRC32calc( dbo.CRC32calc(@crc, (cval / 256)), cval & 0xFF)
    FROM    (   SELECT  v.id, cval = UNICODE(SUBSTRING(@input, v.id, 1))
                FROM    dbo.IndexTable(1, LEN(@input)) AS v
            ) AS t
    ORDER
    BY      t.Id
    ;
    SET @result = CONVERT(int, CONVERT(VARBINARY(4), ~@crc)) ;
    RETURN @result ;
END
GO

【讨论】：

【解决方案4】：

我不认为 T-SQL 让您可以选择使用正确的 CRC 作为校验和函数。仅供参考，SQL Server 集成服务 (SSIS) 确实有一个“校验和”转换，让您可以选择要使用的校验和算法，其中一个选择是：

CRC32 - 使用标准的 32 位循环冗余校验（CRC），这提供更开放的实现。

要在 SQL 中实现 CRC，您可以编写 CRC 的纯 T-SQL 实现（有趣！），或者（如果您使用 SQL Server 2005 或更高版本）用另一种 .NET 语言编写/查找它，然后然后将该类用作已编译的 SQL 存储过程。

【讨论】：

【解决方案5】：

这是一个教育练习，还是您需要在应用程序中实际使用它。如果是第二种，我建议您在应用程序而不是 SQL Server 中执行此操作。如果有替代方法，任何可用的方法，即使是使用 CLR，也可能会更有效，风险更大。大多数选项都会影响 SS 性能。

如果你需要它来验证输入，那么加载它的模块应该在加载时检查（并且可能设置一个状态列。）如果你需要它来输出并且不容易动态计算它，那么让输入模块计算并存储在列中。

如果您想使用它来验证列没有损坏，那么有更好的方法来处理不太可能出现的问题，或者您有一个不稳定的服务器需要处理。

【讨论】：

【解决方案6】：

这是从上面的原始代码帖子派生的非基于表格的解决方案。专家们将不得不权衡这是否比基于表格的解决方案更有效。我的想法是，如果您计算 1,000 条记录的校验和，其中 1 行字符数为 1,000 个字符，那么您对 CRC 查找表执行了 1,000,000 次选择命中，这不会比内存计算更有效.也许是的。

Declare @input as varchar(1000) 
Set @input='This is the CRC test' 
Declare @CRCtable as varchar(3080)   --Location of Edit
Declare @Index as int  
Declare @crc as BIGINT 
Declare @length as INT 
Declare @i as INT 
Declare @tblval as BIGINT  
Declare @CTindex as int 
Declare @ans as varchar(25) 

Set @CRCtable='0000000000, 1996959894, 3993919788, 2567524794, 0124634137, 1886057615, 3915621685, 2657392035, 0249268274, 2044508324, 3772115230, 2547177864, 0162941995, 2125561021, 3887607047, 2428444049, 0498536548, 1789927666, 4089016648, 2227061214, 0450548861, 1843258603, 4107580753, 2211677639, 0325883990, 1684777152, 4251122042, 2321926636, 0335633487, 1661365465, 4195302755, 2366115317, 0997073096, 1281953886, 3579855332, 2724688242, 1006888145, 1258607687, 3524101629, 2768942443, 0901097722, 1119000684, 3686517206, 2898065728, 0853044451, 1172266101, 3705015759, 2882616665, 0651767980, 1373503546, 3369554304, 3218104598, 0565507253, 1454621731, 3485111705, 3099436303, 0671266974, 1594198024, 3322730930, 2970347812, 0795835527, 1483230225, 3244367275, 3060149565, 1994146192, 0031158534, 2563907772, 4023717930, 1907459465, 0112637215, 2680153253, 3904427059, 2013776290, 0251722036, 2517215374, 3775830040, 2137656763, 0141376813, 2439277719, 3865271297, 1802195444, 0476864866, 2238001368, 4066508878, 1812370925, 0453092731, 2181625025, 4111451223, 1706088902, 0314042704, 2344532202, 4240017532, 1658658271, 0366619977, 2362670323, 4224994405, 1303535960, 0984961486, 2747007092, 3569037538, 1256170817, 1037604311, 2765210733, 3554079995, 1131014506, 0879679996, 2909243462, 3663771856, 1141124467, 0855842277, 2852801631, 3708648649, 1342533948, 0654459306, 3188396048, 3373015174, 1466479909, 0544179635, 3110523913, 3462522015, 1591671054, 0702138776, 2966460450, 3352799412, 1504918807, 0783551873, 3082640443, 3233442989, 3988292384, 2596254646, 0062317068, 1957810842, 3939845945, 2647816111, 0081470997, 1943803523, 3814918930, 2489596804, 0225274430, 2053790376, 3826175755, 2466906013, 0167816743, 2097651377, 4027552580, 2265490386, 0503444072, 1762050814, 4150417245, 2154129355, 0426522225, 1852507879, 4275313526, 2312317920, 0282753626, 1742555852, 4189708143, 2394877945, 0397917763, 1622183637, 3604390888, 2714866558, 0953729732, 1340076626, 3518719985, 2797360999, 1068828381, 1219638859, 3624741850, 2936675148, 0906185462, 1090812512, 3747672003, 2825379669, 0829329135, 1181335161, 3412177804, 3160834842, 0628085408, 1382605366, 3423369109, 3138078467, 0570562233, 1426400815, 3317316542, 2998733608, 0733239954, 1555261956, 3268935591, 3050360625, 0752459403, 1541320221, 2607071920, 3965973030, 1969922972, 0040735498, 2617837225, 3943577151, 1913087877, 0083908371, 2512341634, 3803740692, 2075208622, 0213261112, 2463272603, 3855990285, 2094854071, 0198958881, 2262029012, 4057260610, 1759359992, 0534414190, 2176718541, 4139329115, 1873836001, 0414664567, 2282248934, 4279200368, 1711684554, 0285281116, 2405801727, 4167216745, 1634467795, 0376229701, 2685067896, 3608007406, 1308918612, 0956543938, 2808555105, 3495958263, 1231636301, 1047427035, 2932959818, 3654703836, 1088359270, 0936918000, 2847714899, 3736837829, 1202900863, 0817233897, 3183342108, 3401237130, 1404277552, 0615818150, 3134207493, 3453421203, 1423857449, 0601450431, 3009837614, 3294710456, 1567103746, 0711928724, 3020668471, 3272380065, 1510334235, 0755167117, '
Set @crc = 0xFFFFFFFF  
Set @length = LEN(@input)  
Set @i = 1  

While @i <= @length  
  Begin  
  Set @index = ((@crc & 0xff) ^ ASCII(SUBSTRING(@input, @i, 1)))        
  Set @CTindex = (@index * 12) + 1
  Set @ans=substring(@CRCtable,@CTindex,10  )  
  Set @tblval = convert(bigint,@ans) 
  Set @crc = (@crc / 256) ^ @tblval     
  Set @i = @i + 1       
  End  
Set @crc = ~@crc  

SELECT @crc as CRC32, CONVERT(VARBINARY(4), @crc) as CRC32Hex

【讨论】：

不幸的是，这并不总是给出正确的结果。此字符串不起作用“schemenewbusiness/ACM0025/S100/default.aspx”。
找到了，@CRCtable需要是varchar(3080)
为什么在不需要分隔符时使用它们？为什么要使用字符串？与数字数据类型相比，字符串转换和操作非常慢。
另外，查找表是一个表变量，因此可能适合内存。但是现在看看我的回答。

【解决方案7】：

SQL 2005 及之后的版本具有函数CHECKSUM 和CHECKSUM_AGG。这类似于 CRC，可能适用于哈希表或快速检查更改的数据。 CHECKSUM(*) 将返回一个包含单行所有列的值。

我对其进行了简单的测试，它对字符串上的大小写和尾随空格不敏感。如果带有前导或嵌入的空白，它确实会改变。值的顺序很重要。

【讨论】：