Sql-Server
SQL Server UniqueIdentifier / GUID 內部表示
我的一位同事給我發了一個有趣的問題，我無法完全解釋。
他執行了一些程式碼（包括在下面）並從中得到了一些意想不到的結果。
本質上，當將 a
UniqueIdentifier（我將Guid在此處稱為）類型轉換為binary(orvarbinary) 類型時，結果的前半部分的順序是向後的，但後半部分不是。我的第一個想法是系統的字節順序是原因，並且
Guid顯示被保留，但binary不能保證形式。顯然這是一個實現細節，但我想知道是否有一個很好的解釋。
程式碼：
declare @guid uniqueidentifier = '8A737954-CBEC-40CE-A534-2AFFB5A0E207'; declare @binary binary(16) = (select convert(binary(16), @guid)); select @guid as [GUID], @binary as [Binary];結果：
GUID Binary 8A737954-CBEC-40CE-A534-2AFFB5A0E207 0x5479738AECCBCE40A5342AFFB5A0E207如您所見，前半部分
Guid（一直到40CE）為每個部分向後儲存。也就是說，第一個部分Guid是向後的，然後是第二個部分，然後是第三個部分，但是這些部分的順序保持不變。之後，最後兩個部分按照它們在Guid.誰能解釋一下？（下麵包含一個更大的測試集。）
程式碼：
declare @guid_to_binary table ( [id] int identity(1,1), [guid] uniqueidentifier, [binary_conversion] binary(16) ); declare @i int = 1; while @i <= 100 begin insert into @guid_to_binary ( [guid] ) select newid(); set @i = @i + 1; end update @guid_to_binary set binary_conversion = convert(binary(16), [guid]); select * from @guid_to_binary;結果：
id guid binary_conversion 1 EBA4DE58-D35F-46D9-9049-7939381F1A3B 0x58DEA4EB5FD3D94690497939381F1A3B 2 0445A8B7-B2F1-4B35-A4DC-92133570CD69 0xB7A84504F1B2354BA4DC92133570CD69 3 1006278C-1EB6-44A0-B8B0-3392A2EB0922 0x8C270610B61EA044B8B03392A2EB0922 4 EAB330DE-5984-49D6-9B84-F22823A3DB34 0xDE30B3EA8459D6499B84F22823A3DB34 5 25DA0D33-85A3-4AD8-9505-04B85DA6817F 0x330DDA25A385D84A950504B85DA6817F 6 B17B6263-C12B-46C2-BF30-D5AD0F3F765C 0x63627BB12BC1C246BF30D5AD0F3F765C 7 7B58993A-7207-45EC-AE72-B84D4BDE3C1A 0x3A99587B0772EC45AE72B84D4BDE3C1A 8 53772C37-80F6-4DBD-AE3F-3C105E857DFF 0x372C7753F680BD4DAE3F3C105E857DFF 9 D15F9608-CB18-4459-B57A-0D3ACC0421BF 0x08965FD118CB5944B57A0D3ACC0421BF 10 047B539A-80D4-4D22-9E9C-E3642E4AC5E5 0x9A537B04D480224D9E9CE3642E4AC5E5 11 467D192A-AAAF-403E-952D-82EB3B50C123 0x2A197D46AFAA3E40952D82EB3B50C123 12 88F2F0B5-D425-4B29-B774-487BFB30A4F4 0xB5F0F28825D4294BB774487BFB30A4F4 13 99ACBAC2-5F3C-4E57-A83E-088FE4FDA7E9 0xC2BAAC993C5F574EA83E088FE4FDA7E9 14 78D21192-F09B-4C14-B1FB-1DC0617CF23E 0x9211D2789BF0144CB1FB1DC0617CF23E 15 947BBFE5-B6F1-4833-9F44-4F4D6C45C742 0xE5BF7B94F1B633489F444F4D6C45C742 16 B528A36F-776B-4B43-85A2-A17D7D83BF07 0x6FA328B56B77434B85A2A17D7D83BF07 17 434D31D5-A659-475F-AC73-1D59479338F8 0xD5314D4359A65F47AC731D59479338F8 18 A9629EB2-1333-4C26-B5FA-2FB13961324C 0xB29E62A93313264CB5FA2FB13961324C 19 8D2F34CA-ADCB-4497-9568-33EBCE49DADA 0xCA342F8DCBAD9744956833EBCE49DADA 20 5A6A6C52-16AA-4CEF-B6DC-12C6AF40E1F5 0x526C6A5AAA16EF4CB6DC12C6AF40E1F5 21 ED48087D-C9F8-416B-A132-DFE6CBCAD1CF 0x7D0848EDF8C96B41A132DFE6CBCAD1CF 22 D623DF04-A284-4FA6-9CCA-3830E824EA79 0x04DF23D684A2A64F9CCA3830E824EA79 23 918E9032-535F-4FEE-9D28-FF756245A334 0x32908E915F53EE4F9D28FF756245A334 24 2307C209-DF28-4CB4-8A4B-3CB56C9A7094 0x09C2072328DFB44C8A4B3CB56C9A7094 25 9A86F2FE-353D-4BCE-81D0-9CB5BAB04FCA 0xFEF2869A3D35CE4B81D09CB5BAB04FCA 26 4C7D144E-E0E6-4D3C-BC42-D13EBC262096 0x4E147D4CE6E03C4DBC42D13EBC262096 27 AD0290F0-2A44-4FF8-AA82-B9693DF4AC16 0xF09002AD442AF84FAA82B9693DF4AC16 28 A4FC0E4E-0420-4841-AC75-19722D5C4050 0x4E0EFCA420044148AC7519722D5C4050 29 35F08F53-4E26-4CB1-B3AD-FF04898179E1 0x538FF035264EB14CB3ADFF04898179E1 30 5D4CE77D-6FE2-405B-AE1E-3DBB48C990BF 0x7DE74C5DE26F5B40AE1E3DBB48C990BF 31 019E9470-FA72-48D3-A6A3-7EC979BE7D5C 0x70949E0172FAD348A6A37EC979BE7D5C 32 841B906A-97DF-4326-8215-0CE9B0552288 0x6A901B84DF97264382150CE9B0552288 33 62922CA0-E540-490B-9B6D-258C0CF67CB3 0xA02C926240E50B499B6D258C0CF67CB3 34 607BC8CD-96A0-4460-835C-61CFF1DAB602 0xCDC87B60A0966044835C61CFF1DAB602 35 22ED2548-00C1-4E8C-AEA7-7C310CF9DFCD 0x4825ED22C1008C4EAEA77C310CF9DFCD 36 1B88FEB1-E96C-4AFA-BBFA-26A3444E4640 0xB1FE881B6CE9FA4ABBFA26A3444E4640 37 A7BFA1D4-2679-48D6-B4B5-1EB01AA93010 0xD4A1BFA77926D648B4B51EB01AA93010 38 22F3F3B3-D461-48D7-92F9-3BA6CFFFD513 0xB3F3F32261D4D74892F93BA6CFFFD513 39 22934FB8-443B-44C9-81FF-680C4C7D75F5 0xB84F93223B44C94481FF680C4C7D75F5 40 17B54276-0F8B-4FA6-8DDD-BAB02F55E6CC 0x7642B5178B0FA64F8DDDBAB02F55E6CC 41 8AA9D81D-330A-4E97-BE4B-3EA0F5937753 0x1DD8A98A0A33974EBE4B3EA0F5937753 42 50604CA3-5687-4C95-9562-277D29C67B18 0xA34C60508756954C9562277D29C67B18 43 C873B716-AAC5-4D35-BEFE-6B8069963DB8 0x16B773C8C5AA354DBEFE6B8069963DB8 44 E7638B30-A123-45A6-B93A-33DDBC359EA0 0x308B63E723A1A645B93A33DDBC359EA0 45 83F66044-5F98-45C2-A67D-01A1363FCFED 0x4460F683985FC245A67D01A1363FCFED 46 7478BC8F-E530-425B-B2CA-6A31C636F6B4 0x8FBC787430E55B42B2CA6A31C636F6B4 47 4881BB26-851E-4BF7-B62D-5A3DB3B0601C 0x26BB81481E85F74BB62D5A3DB3B0601C 48 C2A9ABB6-EF5E-4BF5-9574-81BEF6699D19 0xB6ABA9C25EEFF54B957481BEF6699D19 49 EB6637F4-08F3-4C4F-B46F-83CC74938562 0xF43766EBF3084F4CB46F83CC74938562 50 629839CE-806E-4F74-B897-A0F624A942F3 0xCE3998626E80744FB897A0F624A942F3 51 C63195B8-0458-46D0-BCA9-2012342145B5 0xB89531C65804D046BCA92012342145B5 52 08928C1B-B481-46D9-898F-84503C8B934C 0x1B8C920881B4D946898F84503C8B934C 53 3D9113FE-20CA-4136-8C6D-A18FAE50F6D0 0xFE13913DCA2036418C6DA18FAE50F6D0 54 83206C44-8F70-4952-83D5-80D8CCD02255 0x446C2083708F524983D580D8CCD02255 55 D591124E-5808-45F3-8A0E-F4BB68B733E5 0x4E1291D50858F3458A0EF4BB68B733E5 56 CE49BC3F-02AC-4536-B2FA-148845ED0EE0 0x3FBC49CEAC023645B2FA148845ED0EE0 57 F9663BCB-17FC-43B7-AF7F-B87518C17A4D 0xCB3B66F9FC17B743AF7FB87518C17A4D 58 BEE8F892-185D-49E7-8AA0-0F48E9404DC5 0x92F8E8BE5D18E7498AA00F48E9404DC5 59 DB9CC990-76C8-4F4B-A480-F82EA3BD3B6D 0x90C99CDBC8764B4FA480F82EA3BD3B6D 60 336ACE62-E185-4D1A-9217-E6A742AEA8A4 0x62CE6A3385E11A4D9217E6A742AEA8A4 61 075FBCEE-F473-40BB-82E2-D419036D9662 0xEEBC5F0773F4BB4082E2D419036D9662 62 255BD1CA-466C-4EBD-A769-0AEDA5ECDCBF 0xCAD15B256C46BD4EA7690AEDA5ECDCBF 63 604D2442-F88A-4034-9F8D-D0E36904A013 0x42244D608AF834409F8DD0E36904A013 64 0D58AAC6-47F1-4ACE-918C-AFFB639A45AB 0xC6AA580DF147CE4A918CAFFB639A45AB 65 8EE4C9E5-9C69-47A4-B4AB-6DF56FAFDD17 0xE5C9E48E699CA447B4AB6DF56FAFDD17 66 2EBA4B09-99EF-42A4-8BDF-C1F4EAEB37DD 0x094BBA2EEF99A4428BDFC1F4EAEB37DD 67 B25B5C1B-9233-411B-A781-D7F8427DB93A 0x1B5C5BB233921B41A781D7F8427DB93A 68 8747A125-F8DD-426F-8B31-A11DE7FED067 0x25A14787DDF86F428B31A11DE7FED067 69 744CE50A-5CCE-4A65-A502-3C165E7C1A13 0x0AE54C74CE5C654AA5023C165E7C1A13 70 AB990702-7B8C-427F-A1FF-22A2236B3BB2 0x020799AB8C7B7F42A1FF22A2236B3BB2 71 CDBFF8A2-7C4C-429C-AF0D-8D6AB1F376F6 0xA2F8BFCD4C7C9C42AF0D8D6AB1F376F6 72 0558FA3A-FF34-4A02-A32F-8017BBE0D98E 0x3AFA580534FF024AA32F8017BBE0D98E 73 C42E5C3B-7CEB-4B13-B0C7-B1A5436FA95F 0x3B5C2EC4EB7C134BB0C7B1A5436FA95F 74 B577B02E-2925-4F07-ABA0-FC981C126C0A 0x2EB077B52529074FABA0FC981C126C0A 75 20C77BE2-656B-4E4E-89AC-1E07D11B595F 0xE27BC7206B654E4E89AC1E07D11B595F 76 7192D091-B9B3-4D48-B44B-EC7ACDDEB800 0x91D09271B3B9484DB44BEC7ACDDEB800 77 6BD846C9-5EB8-40DE-92DB-844E3DF1827D 0xC946D86BB85EDE4092DB844E3DF1827D 78 009B2D21-1545-4C15-966E-D5EC31B45BE5 0x212D9B004515154C966ED5EC31B45BE5 79 7554AB43-1E1B-47CC-8AAA-248C86A590FA 0x43AB54751B1ECC478AAA248C86A590FA 80 6F46275B-F85F-426F-A9F6-6D923BA1F055 0x5B27466F5FF86F42A9F66D923BA1F055 81 63697CB0-68C8-4F91-9CCB-F28B04345F3A 0xB07C6963C868914F9CCBF28B04345F3A 82 7C3C36B0-7B71-4E8B-A14A-884CF61B3368 0xB0363C7C717B8B4EA14A884CF61B3368 83 8DBA33D7-83BC-4D74-A219-7AA0E25104FD 0xD733BA8DBC83744DA2197AA0E25104FD 84 917E3848-A028-41A4-9BC4-BA40625F1FF7 0x48387E9128A0A4419BC4BA40625F1FF7 85 9B87B6BA-7256-44F2-8AB7-516F8D906056 0xBAB6879B5672F2448AB7516F8D906056 86 6837D3BB-91FD-4E2A-AED5-6B8017004C54 0xBBD33768FD912A4EAED56B8017004C54 87 8E9FCD91-D9B4-465E-B1DF-2C3126FFA402 0x91CD9F8EB4D95E46B1DF2C3126FFA402 88 CB2E6016-5B09-40B5-AFD2-C989724DFED0 0x16602ECB095BB540AFD2C989724DFED0 89 F282E16A-068E-49D2-B65C-915214D06A04 0x6AE182F28E06D249B65C915214D06A04 90 6EDA33EB-8482-4BD8-9979-BB278C8D2C6F 0xEB33DA6E8284D84B9979BB278C8D2C6F 91 F4DC0E3B-B693-42C5-B5BD-07FC1A9AE8B9 0x3B0EDCF493B6C542B5BD07FC1A9AE8B9 92 24F12333-1B03-4EC4-A9A2-308A6F3CE996 0x3323F124031BC44EA9A2308A6F3CE996 93 5CCB94FC-F846-4EF3-ACF8-1DBAA0EB5405 0xFC94CB5C46F8F34EACF81DBAA0EB5405 94 9E8BC4B4-528F-42E3-B403-1A55F74420C3 0xB4C48B9E8F52E342B4031A55F74420C3 95 9F1BF452-31EC-486A-B572-4338319FC67E 0x52F41B9FEC316A48B5724338319FC67E 96 00B72F09-78AD-4BE5-9785-FA2939DE581A 0x092FB700AD78E54B9785FA2939DE581A 97 EC5A3AEF-3255-424D-8174-CBAEE0A2D243 0xEF3A5AEC55324D428174CBAEE0A2D243 98 48BC3E92-F3FA-47B8-881E-431D43118C99 0x923EBC48FAF3B847881E431D43118C99 99 C72A84F3-E961-4F6E-87AA-7A12D2EAD032 0xF3842AC761E96E4F87AA7A12D2EAD032 100 3F0E1666-BD80-4562-8FE3-CFA2009FDD08 0x66160E3F80BD62458FE3CFA2009FDD08
根據關於全球唯一標識符的 Wikipedia 文章（在“二進制編碼”部分），Microsoft 的 GUID 實現在前半部分（前 8 個字節）使用“本機”字節序，對後 8 個字節使用大字節序編碼。Microsoft Windows 和 SQL Server 是“Little Endian”，因為 Intel 架構是 Little Endian，因此“Native”意味著“Little Endian”。以下圖表是從該 Wikipedia 文章中復製而來的：
Bits Bytes Name Endianness 32 4 Data1 Native 16 2 Data2 Native 16 2 Data3 Native 64 8 Data4 Big關於 Microsoft SQL Server 的 Little Endianness，Collation and Unicode Support MSDN 頁面指出：
因為英特爾平台是小端架構，Unicode 程式碼字元總是以字節交換的方式儲存。