SQL Server CheckSum是否计算CRC？如果不是,我如何让SQL Server在任意varchar列上计算CRC？
我对模型的粗糙性表示歉意，但这似乎做了正确的 CRC32 计算。我不是 TSQL 专家，但我确信真正的 SQL Server 专业人员可以极大地改进这一点...
@input 是计算 CRC32 的变量。将其打包为存储过程或 udf 应该很简单，并且查找表可以分解为永久表（甚至可以动态计算）。
无论如何，它似乎有效。我很想看到任何改进，因为学习新技巧总是好的:)
编辑：我已经根据http://crc32-checksum.waraxe.us/检查了我的结果，到目前为止看起来不错。
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)
INSERT INTO @tblLookup VALUES (2428444049)
INSERT INTO @tblLookup VALUES (498536548)
INSERT INTO @tblLookup VALUES (1789927666)
INSERT INTO @tblLookup VALUES (4089016648)
INSERT INTO @tblLookup VALUES (2227061214)
INSERT INTO @tblLookup VALUES (450548861)
INSERT INTO @tblLookup VALUES (1843258603)
INSERT INTO @tblLookup VALUES (4107580753)
INSERT INTO @tblLookup VALUES (2211677639)
INSERT INTO @tblLookup VALUES (325883990)
INSERT INTO @tblLookup VALUES (1684777152)
INSERT INTO @tblLookup VALUES (4251122042)
INSERT INTO @tblLookup VALUES (2321926636)
INSERT INTO @tblLookup VALUES (335633487)
INSERT INTO @tblLookup VALUES (1661365465)
INSERT INTO @tblLookup VALUES (4195302755)
INSERT INTO @tblLookup VALUES (2366115317)
INSERT INTO @tblLookup VALUES (997073096)
INSERT INTO @tblLookup VALUES (1281953886)
INSERT INTO @tblLookup VALUES (3579855332)
INSERT INTO @tblLookup VALUES (2724688242)
INSERT INTO @tblLookup VALUES (1006888145)
INSERT INTO @tblLookup VALUES (1258607687)
INSERT INTO @tblLookup VALUES (3524101629)
INSERT INTO @tblLookup VALUES (2768942443)
INSERT INTO @tblLookup VALUES (901097722)
INSERT INTO @tblLookup VALUES (1119000684)
INSERT INTO @tblLookup VALUES (3686517206)
INSERT INTO @tblLookup VALUES (2898065728)
INSERT INTO @tblLookup VALUES (853044451)
INSERT INTO @tblLookup VALUES (1172266101)
INSERT INTO @tblLookup VALUES (3705015759)
INSERT INTO @tblLookup VALUES (2882616665)
INSERT INTO @tblLookup VALUES (651767980)
INSERT INTO @tblLookup VALUES (1373503546)
INSERT INTO @tblLookup VALUES (3369554304)
INSERT INTO @tblLookup VALUES (3218104598)
INSERT INTO @tblLookup VALUES (565507253)
INSERT INTO @tblLookup VALUES (1454621731)
INSERT INTO @tblLookup VALUES (3485111705)
INSERT INTO @tblLookup VALUES (3099436303)
INSERT INTO @tblLookup VALUES (671266974)
INSERT INTO @tblLookup VALUES (1594198024)
INSERT INTO @tblLookup VALUES (3322730930)
INSERT INTO @tblLookup VALUES (2970347812)
INSERT INTO @tblLookup VALUES (795835527)
INSERT INTO @tblLookup VALUES (1483230225)
INSERT INTO @tblLookup VALUES (3244367275)
INSERT INTO @tblLookup VALUES (3060149565)
INSERT INTO @tblLookup VALUES (1994146192)
INSERT INTO @tblLookup VALUES (31158534)
INSERT INTO @tblLookup VALUES (2563907772)
INSERT INTO @tblLookup VALUES (4023717930)
INSERT INTO @tblLookup VALUES (1907459465)
INSERT INTO @tblLookup VALUES (112637215)
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INSERT INTO @tblLookup VALUES (1658658271)
INSERT INTO @tblLookup VALUES (366619977)
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INSERT INTO @tblLookup VALUES (3110523913)
INSERT INTO @tblLookup VALUES (3462522015)
INSERT INTO @tblLookup VALUES (1591671054)
INSERT INTO @tblLookup VALUES (702138776)
INSERT INTO @tblLookup VALUES (2966460450)
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INSERT INTO @tblLookup VALUES (1504918807)
INSERT INTO @tblLookup VALUES (783551873)
INSERT INTO @tblLookup VALUES (3082640443)
INSERT INTO @tblLookup VALUES (3233442989)
INSERT INTO @tblLookup VALUES (3988292384)
INSERT INTO @tblLookup VALUES (2596254646)
INSERT INTO @tblLookup VALUES (62317068)
INSERT INTO @tblLookup VALUES (1957810842)
INSERT INTO @tblLookup VALUES (3939845945)
INSERT INTO @tblLookup VALUES (2647816111)
INSERT INTO @tblLookup VALUES (81470997)
INSERT INTO @tblLookup VALUES (1943803523)
INSERT INTO @tblLookup VALUES (3814918930)
INSERT INTO @tblLookup VALUES (2489596804)
INSERT INTO @tblLookup VALUES (225274430)
INSERT INTO @tblLookup VALUES (2053790376)
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INSERT INTO @tblLookup VALUES (167816743)
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INSERT INTO @tblLookup VALUES (2607071920)
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INSERT INTO @tblLookup VALUES (1969922972)
INSERT INTO @tblLookup VALUES (40735498)
INSERT INTO @tblLookup VALUES (2617837225)
INSERT INTO @tblLookup VALUES (3943577151)
INSERT INTO @tblLookup VALUES (1913087877)
INSERT INTO @tblLookup VALUES (83908371)
INSERT INTO @tblLookup VALUES (2512341634)
INSERT INTO @tblLookup VALUES (3803740692)
INSERT INTO @tblLookup VALUES (2075208622)
INSERT INTO @tblLookup VALUES (213261112)
INSERT INTO @tblLookup VALUES (2463272603)
INSERT INTO @tblLookup VALUES (3855990285)
INSERT INTO @tblLookup VALUES (2094854071)
INSERT INTO @tblLookup VALUES (198958881)
INSERT INTO @tblLookup VALUES (2262029012)
INSERT INTO @tblLookup VALUES (4057260610)
INSERT INTO @tblLookup VALUES (1759359992)
INSERT INTO @tblLookup VALUES (534414190)
INSERT INTO @tblLookup VALUES (2176718541)
INSERT INTO @tblLookup VALUES (4139329115)
INSERT INTO @tblLookup VALUES (1873836001)
INSERT INTO @tblLookup VALUES (414664567)
INSERT INTO @tblLookup VALUES (2282248934)
INSERT INTO @tblLookup VALUES (4279200368)
INSERT INTO @tblLookup VALUES (1711684554)
INSERT INTO @tblLookup VALUES (285281116)
INSERT INTO @tblLookup VALUES (2405801727)
INSERT INTO @tblLookup VALUES (4167216745)
INSERT INTO @tblLookup VALUES (1634467795)
INSERT INTO @tblLookup VALUES (376229701)
INSERT INTO @tblLookup VALUES (2685067896)
INSERT INTO @tblLookup VALUES (3608007406)
INSERT INTO @tblLookup VALUES (1308918612)
INSERT INTO @tblLookup VALUES (956543938)
INSERT INTO @tblLookup VALUES (2808555105)
INSERT INTO @tblLookup VALUES (3495958263)
INSERT INTO @tblLookup VALUES (1231636301)
INSERT INTO @tblLookup VALUES (1047427035)
INSERT INTO @tblLookup VALUES (2932959818)
INSERT INTO @tblLookup VALUES (3654703836)
INSERT INTO @tblLookup VALUES (1088359270)
INSERT INTO @tblLookup VALUES (936918000)
INSERT INTO @tblLookup VALUES (2847714899)
INSERT INTO @tblLookup VALUES (3736837829)
INSERT INTO @tblLookup VALUES (1202900863)
INSERT INTO @tblLookup VALUES (817233897)
INSERT INTO @tblLookup VALUES (3183342108)
INSERT INTO @tblLookup VALUES (3401237130)
INSERT INTO @tblLookup VALUES (1404277552)
INSERT INTO @tblLookup VALUES (615818150)
INSERT INTO @tblLookup VALUES (3134207493)
INSERT INTO @tblLookup VALUES (3453421203)
INSERT INTO @tblLookup VALUES (1423857449)
INSERT INTO @tblLookup VALUES (601450431)
INSERT INTO @tblLookup VALUES (3009837614)
INSERT INTO @tblLookup VALUES (3294710456)
INSERT INTO @tblLookup VALUES (1567103746)
INSERT INTO @tblLookup VALUES (711928724)
INSERT INTO @tblLookup VALUES (3020668471)
INSERT INTO @tblLookup VALUES (3272380065)
INSERT INTO @tblLookup VALUES (1510334235)
INSERT INTO @tblLookup VALUES (755167117)
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
我将安德鲁·罗林斯 (Andrew Rollings) 的剧本缩短为 11 行，因此他确实获得了荣誉。这将在 SQL 2008 或更高版本中运行。如果您在DECLARE之后设置变量值，它将在SQL 2005中运行。在2005年及以上，字符限制是2048，在SQL 2000中它类似于512（我不记得SQL中有多少个P类型的spt_values） 2000）。但如有必要，可以对此进行修改。
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;