\u6765\u81ea\uff1achinaunix \u4f5c\u8005\uff1auunguymadman007\u98ce\u4e91\u4f7f\u8005
\u4e00\u3001\u95ee\u9898\u7684\u63d0\u51fa
\u5728\u5e94\u7528\u7cfb\u7edf\u5f00\u53d1\u521d\u671f\uff0c\u7531\u4e8e\u5f00\u53d1\u6570\u636e\u5e93\u6570\u636e\u6bd4\u8f83\u5c11\uff0c\u5bf9\u4e8e\u67e5\u8be2SQL\u8bed\u53e5\uff0c\u590d\u6742\u89c6\u56fe\u7684\u7684\u7f16\u5199\u7b49\u4f53\u4f1a\u4e0d\u51faSQL\u8bed\u53e5\u5404\u79cd\u5199\u6cd5\u7684\u6027\u80fd\u4f18\u52a3\uff0c\u4f46\u662f\u5982\u679c\u5c06\u5e94\u7528\u7cfb\u7edf\u63d0\u4ea4\u5b9e\u9645\u5e94\u7528\u540e\uff0c\u968f\u7740\u6570\u636e\u5e93\u4e2d\u6570\u636e\u7684\u589e\u52a0\uff0c\u7cfb\u7edf\u7684\u54cd\u5e94\u901f\u5ea6\u5c31\u6210\u4e3a\u76ee\u524d\u7cfb\u7edf\u9700\u8981\u89e3\u51b3\u7684\u6700\u4e3b\u8981\u7684\u95ee\u9898\u4e4b\u4e00\u3002\u7cfb\u7edf\u4f18\u5316\u4e2d\u4e00\u4e2a\u5f88\u91cd\u8981\u7684\u65b9\u9762\u5c31\u662fSQL\u8bed\u53e5\u7684\u4f18\u5316\u3002\u5bf9\u4e8e\u6d77\u91cf\u6570\u636e\uff0c\u52a3\u8d28SQL\u8bed\u53e5\u548c\u4f18\u8d28SQL\u8bed\u53e5\u4e4b\u95f4\u7684\u901f\u5ea6\u5dee\u522b\u53ef\u4ee5\u8fbe\u5230\u4e0a\u767e\u500d\uff0c\u53ef\u89c1\u5bf9\u4e8e\u4e00\u4e2a\u7cfb\u7edf\u4e0d\u662f\u7b80\u5355\u5730\u80fd\u5b9e\u73b0\u5176\u529f\u80fd\u5c31\u53ef\uff0c\u800c\u662f\u8981\u5199\u51fa\u9ad8\u8d28\u91cf\u7684SQL\u8bed\u53e5\uff0c\u63d0\u9ad8\u7cfb\u7edf\u7684\u53ef\u7528\u6027\u3002
\u5728\u591a\u6570\u60c5\u51b5\u4e0b\uff0cOracle\u4f7f\u7528\u7d22\u5f15\u6765\u66f4\u5feb\u5730\u904d\u5386\u8868\uff0c\u4f18\u5316\u5668\u4e3b\u8981\u6839\u636e\u5b9a\u4e49\u7684\u7d22\u5f15\u6765\u63d0\u9ad8\u6027\u80fd\u3002\u4f46\u662f\uff0c\u5982\u679c\u5728SQL\u8bed\u53e5\u7684where\u5b50\u53e5\u4e2d\u5199\u7684SQL\u4ee3\u7801\u4e0d\u5408\u7406\uff0c\u5c31\u4f1a\u9020\u6210\u4f18\u5316\u5668\u5220\u53bb\u7d22\u5f15\u800c\u4f7f\u7528\u5168\u8868\u626b\u63cf\uff0c\u4e00\u822c\u5c31\u8fd9\u79cdSQL\u8bed\u53e5\u5c31\u662f\u6240\u8c13\u7684\u52a3\u8d28SQL\u8bed\u53e5\u3002\u5728\u7f16\u5199SQL\u8bed\u53e5\u65f6\u6211\u4eec\u5e94\u6e05\u695a\u4f18\u5316\u5668\u6839\u636e\u4f55\u79cd\u539f\u5219\u6765\u5220\u9664\u7d22\u5f15\uff0c\u8fd9\u6709\u52a9\u4e8e\u5199\u51fa\u9ad8\u6027\u80fd\u7684SQL\u8bed\u53e5\u3002
\u4e8c\u3001SQL\u8bed\u53e5\u7f16\u5199\u6ce8\u610f\u95ee\u9898
\u4e0b\u9762\u5c31\u67d0\u4e9bSQL\u8bed\u53e5\u7684where\u5b50\u53e5\u7f16\u5199\u4e2d\u9700\u8981\u6ce8\u610f\u7684\u95ee\u9898\u4f5c\u8be6\u7ec6\u4ecb\u7ecd\u3002\u5728\u8fd9\u4e9bwhere\u5b50\u53e5\u4e2d\uff0c\u5373\u4f7f\u67d0\u4e9b\u5217\u5b58\u5728\u7d22\u5f15\uff0c\u4f46\u662f\u7531\u4e8e\u7f16\u5199\u4e86\u52a3\u8d28\u7684SQL\uff0c\u7cfb\u7edf\u5728\u8fd0\u884c\u8be5SQL\u8bed\u53e5\u65f6\u4e5f\u4e0d\u80fd\u4f7f\u7528\u8be5\u7d22\u5f15\uff0c\u800c\u540c\u6837\u4f7f\u7528\u5168\u8868\u626b\u63cf\uff0c\u8fd9\u5c31\u9020\u6210\u4e86\u54cd\u5e94\u901f\u5ea6\u7684\u6781\u5927\u964d\u4f4e\u3002
1. IS NULL \u4e0e IS NOT NULL
\u4e0d\u80fd\u7528null\u4f5c\u7d22\u5f15\uff0c\u4efb\u4f55\u5305\u542bnull\u503c\u7684\u5217\u90fd\u5c06\u4e0d\u4f1a\u88ab\u5305\u542b\u5728\u7d22\u5f15\u4e2d\u3002\u5373\u4f7f\u7d22\u5f15\u6709\u591a\u5217\u8fd9\u6837\u7684\u60c5\u51b5\u4e0b\uff0c\u53ea\u8981\u8fd9\u4e9b\u5217\u4e2d\u6709\u4e00\u5217\u542b\u6709null\uff0c\u8be5\u5217\u5c31\u4f1a\u4ece\u7d22\u5f15\u4e2d\u6392\u9664\u3002\u4e5f\u5c31\u662f\u8bf4\u5982\u679c\u67d0\u5217\u5b58\u5728\u7a7a\u503c\uff0c\u5373\u4f7f\u5bf9\u8be5\u5217\u5efa\u7d22\u5f15\u4e5f\u4e0d\u4f1a\u63d0\u9ad8\u6027\u80fd\u3002
\u4efb\u4f55\u5728where\u5b50\u53e5\u4e2d\u4f7f\u7528is null\u6216is not null\u7684\u8bed\u53e5\u4f18\u5316\u5668\u662f\u4e0d\u5141\u8bb8\u4f7f\u7528\u7d22\u5f15\u7684\u3002
2. \u8054\u63a5\u5217
\u5bf9\u4e8e\u6709\u8054\u63a5\u7684\u5217\uff0c\u5373\u4f7f\u6700\u540e\u7684\u8054\u63a5\u503c\u4e3a\u4e00\u4e2a\u9759\u6001\u503c\uff0c\u4f18\u5316\u5668\u662f\u4e0d\u4f1a\u4f7f\u7528\u7d22\u5f15\u7684\u3002\u6211\u4eec\u4e00\u8d77\u6765\u770b\u4e00\u4e2a\u4f8b\u5b50\uff0c\u5047\u5b9a\u6709\u4e00\u4e2a\u804c\u5de5\u8868\uff08employee\uff09\uff0c\u5bf9\u4e8e\u4e00\u4e2a\u804c\u5de5\u7684\u59d3\u548c\u540d\u5206\u6210\u4e24\u5217\u5b58\u653e\uff08FIRST_NAME\u548cLAST_NAME\uff09\uff0c\u73b0\u5728\u8981\u67e5\u8be2\u4e00\u4e2a\u53eb\u6bd4\u5c14.\u514b\u6797\u987f\uff08Bill Cliton\uff09\u7684\u804c\u5de5\u3002
\u4e0b\u9762\u662f\u4e00\u4e2a\u91c7\u7528\u8054\u63a5\u67e5\u8be2\u7684SQL\u8bed\u53e5\uff0c
select * from employss
where
first_name||”||last_name =’Beill Cliton’
\u4e0a\u9762\u8fd9\u6761\u8bed\u53e5\u5b8c\u5168\u53ef\u4ee5\u67e5\u8be2\u51fa\u662f\u5426\u6709Bill Cliton\u8fd9\u4e2a\u5458\u5de5\uff0c\u4f46\u662f\u8fd9\u91cc\u9700\u8981\u6ce8\u610f\uff0c\u7cfb\u7edf\u4f18\u5316\u5668\u5bf9\u57fa\u4e8elast_name\u521b\u5efa\u7684\u7d22\u5f15\u6ca1\u6709\u4f7f\u7528\u3002
\u5f53\u91c7\u7528\u4e0b\u9762\u8fd9\u79cdSQL\u8bed\u53e5\u7684\u7f16\u5199\uff0cOracle\u7cfb\u7edf\u5c31\u53ef\u4ee5\u91c7\u7528\u57fa\u4e8elast_name\u521b\u5efa\u7684\u7d22\u5f15\u3002
Select * from employee
where
first_name =’Beill’ and last_name =’Cliton’
\u9047\u5230\u4e0b\u9762\u8fd9\u79cd\u60c5\u51b5\u53c8\u5982\u4f55\u5904\u7406\u5462\uff1f\u5982\u679c\u4e00\u4e2a\u53d8\u91cf\uff08name\uff09\u4e2d\u5b58\u653e\u7740Bill Cliton\u8fd9\u4e2a\u5458\u5de5\u7684\u59d3\u540d\uff0c\u5bf9\u4e8e\u8fd9\u79cd\u60c5\u51b5\u6211\u4eec\u53c8\u5982\u4f55\u907f\u514d\u5168\u7a0b\u904d\u5386\uff0c\u4f7f\u7528\u7d22\u5f15\u5462\uff1f\u53ef\u4ee5\u4f7f\u7528\u4e00\u4e2a\u51fd\u6570\uff0c\u5c06\u53d8\u91cfname\u4e2d\u7684\u59d3\u548c\u540d\u5206\u5f00\u5c31\u53ef\u4ee5\u4e86\uff0c\u4f46\u662f\u6709\u4e00\u70b9\u9700\u8981\u6ce8\u610f\uff0c\u8fd9\u4e2a\u51fd\u6570\u662f\u4e0d\u80fd\u4f5c\u7528\u5728\u7d22\u5f15\u5217\u4e0a\u3002\u4e0b\u9762\u662fSQL\u67e5\u8be2\u811a\u672c\uff1a
select * from employee
where
first_name = SUBSTR(‘&&name’,1,INSTR(‘&&name’,’ ‘)-1)
and
last_name = SUBSTR(‘&&name’,INSTR(‘&&name\u2019,’ ‘)+1)
3. \u5e26\u901a\u914d\u7b26\uff08%\uff09\u7684like\u8bed\u53e5
\u540c\u6837\u4ee5\u4e0a\u9762\u7684\u4f8b\u5b50\u6765\u770b\u8fd9\u79cd\u60c5\u51b5\u3002\u76ee\u524d\u7684\u9700\u6c42\u662f\u8fd9\u6837\u7684\uff0c\u8981\u6c42\u5728\u804c\u5de5\u8868\u4e2d\u67e5\u8be2\u540d\u5b57\u4e2d\u5305\u542bcliton\u7684\u4eba\u3002\u53ef\u4ee5\u91c7\u7528\u5982\u4e0b\u7684\u67e5\u8be2SQL\u8bed\u53e5\uff1a
select * from employee where last_name like ‘%cliton%’
\u8fd9\u91cc\u7531\u4e8e\u901a\u914d\u7b26\uff08%\uff09\u5728\u641c\u5bfb\u8bcd\u9996\u51fa\u73b0\uff0c\u6240\u4ee5Oracle\u7cfb\u7edf\u4e0d\u4f7f\u7528last_name\u7684\u7d22\u5f15\u3002\u5728\u5f88\u591a\u60c5\u51b5\u4e0b\u53ef\u80fd\u65e0\u6cd5\u907f\u514d\u8fd9\u79cd\u60c5\u51b5\uff0c\u4f46\u662f\u4e00\u5b9a\u8981\u5fc3\u4e2d\u6709\u5e95\uff0c\u901a\u914d\u7b26\u5982\u6b64\u4f7f\u7528\u4f1a\u964d\u4f4e\u67e5\u8be2\u901f\u5ea6\u3002\u7136\u800c\u5f53\u901a\u914d\u7b26\u51fa\u73b0\u5728\u5b57\u7b26\u4e32\u5176\u4ed6\u4f4d\u7f6e\u65f6\uff0c\u4f18\u5316\u5668\u5c31\u80fd\u5229\u7528\u7d22\u5f15\u3002\u5728\u4e0b\u9762\u7684\u67e5\u8be2\u4e2d\u7d22\u5f15\u5f97\u5230\u4e86\u4f7f\u7528\uff1a
select * from employee where last_name like ‘c%’
4. Order by\u8bed\u53e5
ORDER BY\u8bed\u53e5\u51b3\u5b9a\u4e86Oracle\u5982\u4f55\u5c06\u8fd4\u56de\u7684\u67e5\u8be2\u7ed3\u679c\u6392\u5e8f\u3002Order by\u8bed\u53e5\u5bf9\u8981\u6392\u5e8f\u7684\u5217\u6ca1\u6709\u4ec0\u4e48\u7279\u522b\u7684\u9650\u5236\uff0c\u4e5f\u53ef\u4ee5\u5c06\u51fd\u6570\u52a0\u5165\u5217\u4e2d\uff08\u8c61\u8054\u63a5\u6216\u8005\u9644\u52a0\u7b49\uff09\u3002\u4efb\u4f55\u5728Order by\u8bed\u53e5\u7684\u975e\u7d22\u5f15\u9879\u6216\u8005\u6709\u8ba1\u7b97\u8868\u8fbe\u5f0f\u90fd\u5c06\u964d\u4f4e\u67e5\u8be2\u901f\u5ea6\u3002
\u4ed4\u7ec6\u68c0\u67e5order by\u8bed\u53e5\u4ee5\u627e\u51fa\u975e\u7d22\u5f15\u9879\u6216\u8005\u8868\u8fbe\u5f0f\uff0c\u5b83\u4eec\u4f1a\u964d\u4f4e\u6027\u80fd\u3002\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\u7684\u529e\u6cd5\u5c31\u662f\u91cd\u5199order by\u8bed\u53e5\u4ee5\u4f7f\u7528\u7d22\u5f15\uff0c\u4e5f\u53ef\u4ee5\u4e3a\u6240\u4f7f\u7528\u7684\u5217\u5efa\u7acb\u53e6\u5916\u4e00\u4e2a\u7d22\u5f15\uff0c\u540c\u65f6\u5e94\u7edd\u5bf9\u907f\u514d\u5728order by\u5b50\u53e5\u4e2d\u4f7f\u7528\u8868\u8fbe\u5f0f\u3002
5. NOT
\u6211\u4eec\u5728\u67e5\u8be2\u65f6\u7ecf\u5e38\u5728where\u5b50\u53e5\u4f7f\u7528\u4e00\u4e9b\u903b\u8f91\u8868\u8fbe\u5f0f\uff0c\u5982\u5927\u4e8e\u3001\u5c0f\u4e8e\u3001\u7b49\u4e8e\u4ee5\u53ca\u4e0d\u7b49\u4e8e\u7b49\u7b49\uff0c\u4e5f\u53ef\u4ee5\u4f7f\u7528and\uff08\u4e0e\uff09\u3001or\uff08\u6216\uff09\u4ee5\u53canot\uff08\u975e\uff09\u3002NOT\u53ef\u7528\u6765\u5bf9\u4efb\u4f55\u903b\u8f91\u8fd0\u7b97\u7b26\u53f7\u53d6\u53cd\u3002\u4e0b\u9762\u662f\u4e00\u4e2aNOT\u5b50\u53e5\u7684\u4f8b\u5b50\uff1a
… where not (status =’VALID’)
\u5982\u679c\u8981\u4f7f\u7528NOT\uff0c\u5219\u5e94\u5728\u53d6\u53cd\u7684\u77ed\u8bed\u524d\u9762\u52a0\u4e0a\u62ec\u53f7\uff0c\u5e76\u5728\u77ed\u8bed\u524d\u9762\u52a0\u4e0aNOT\u8fd0\u7b97\u7b26\u3002NOT\u8fd0\u7b97\u7b26\u5305\u542b\u5728\u53e6\u5916\u4e00\u4e2a\u903b\u8f91\u8fd0\u7b97\u7b26\u4e2d\uff0c\u8fd9\u5c31\u662f\u4e0d\u7b49\u4e8e\uff08<>$$\uff09\u8fd0\u7b97\u7b26\u3002\u6362\u53e5\u8bdd\u8bf4\uff0c\u5373\u4f7f\u4e0d\u5728\u67e5\u8be2where\u5b50\u53e5\u4e2d\u663e\u5f0f\u5730\u52a0\u5165NOT\u8bcd\uff0cNOT\u4ecd\u5728\u8fd0\u7b97\u7b26\u4e2d\uff0c\u89c1\u4e0b\u4f8b\uff1a
… where status <>$$’INVALID’
\u518d\u770b\u4e0b\u9762\u8fd9\u4e2a\u4f8b\u5b50\uff1a
select * from employee where salary<>$$3000;
\u5bf9\u8fd9\u4e2a\u67e5\u8be2\uff0c\u53ef\u4ee5\u6539\u5199\u4e3a\u4e0d\u4f7f\u7528NOT\uff1a
select * from employee where salary<3000 or salary>$$3000;
\u867d\u7136\u8fd9\u4e24\u79cd\u67e5\u8be2\u7684\u7ed3\u679c\u4e00\u6837\uff0c\u4f46\u662f\u7b2c\u4e8c\u79cd\u67e5\u8be2\u65b9\u6848\u4f1a\u6bd4\u7b2c\u4e00\u79cd\u67e5\u8be2\u65b9\u6848\u66f4\u5feb\u4e9b\u3002\u7b2c\u4e8c\u79cd\u67e5\u8be2\u5141\u8bb8Oracle\u5bf9salary\u5217\u4f7f\u7528\u7d22\u5f15\uff0c\u800c\u7b2c\u4e00\u79cd\u67e5\u8be2\u5219\u4e0d\u80fd\u4f7f\u7528\u7d22\u5f15\u3002
6. IN\u548cEXISTS
\u6709\u65f6\u5019\u4f1a\u5c06\u4e00\u5217\u548c\u4e00\u7cfb\u5217\u503c\u76f8\u6bd4\u8f83\u3002\u6700\u7b80\u5355\u7684\u529e\u6cd5\u5c31\u662f\u5728where\u5b50\u53e5\u4e2d\u4f7f\u7528\u5b50\u67e5\u8be2\u3002\u5728where\u5b50\u53e5\u4e2d\u53ef\u4ee5\u4f7f\u7528\u4e24\u79cd\u683c\u5f0f\u7684\u5b50\u67e5\u8be2\u3002
\u7b2c\u4e00\u79cd\u683c\u5f0f\u662f\u4f7f\u7528IN\u64cd\u4f5c\u7b26\uff1a
… where column in(select * from … where …);
\u7b2c\u4e8c\u79cd\u683c\u5f0f\u662f\u4f7f\u7528EXIST\u64cd\u4f5c\u7b26\uff1a
… where exists (select ‘X’ from …where …);
\u6211\u76f8\u4fe1\u7edd\u5927\u591a\u6570\u4eba\u4f1a\u4f7f\u7528\u7b2c\u4e00\u79cd\u683c\u5f0f\uff0c\u56e0\u4e3a\u5b83\u6bd4\u8f83\u5bb9\u6613\u7f16\u5199\uff0c\u800c\u5b9e\u9645\u4e0a\u7b2c\u4e8c\u79cd\u683c\u5f0f\u8981\u8fdc\u6bd4\u7b2c\u4e00\u79cd\u683c\u5f0f\u7684\u6548\u7387\u9ad8\u3002\u5728Oracle\u4e2d\u53ef\u4ee5\u51e0\u4e4e\u5c06\u6240\u6709\u7684IN\u64cd\u4f5c\u7b26\u5b50\u67e5\u8be2\u6539\u5199\u4e3a\u4f7f\u7528EXISTS\u7684\u5b50\u67e5\u8be2\u3002
\u7b2c\u4e8c\u79cd\u683c\u5f0f\u4e2d\uff0c\u5b50\u67e5\u8be2\u4ee5\u2018select ‘X’\u5f00\u59cb\u3002\u8fd0\u7528EXISTS\u5b50\u53e5\u4e0d\u7ba1\u5b50\u67e5\u8be2\u4ece\u8868\u4e2d\u62bd\u53d6\u4ec0\u4e48\u6570\u636e\u5b83\u53ea\u67e5\u770bwhere\u5b50\u53e5\u3002\u8fd9\u6837\u4f18\u5316\u5668\u5c31\u4e0d\u5fc5\u904d\u5386\u6574\u4e2a\u8868\u800c\u4ec5\u6839\u636e\u7d22\u5f15\u5c31\u53ef\u5b8c\u6210\u5de5\u4f5c\uff08\u8fd9\u91cc\u5047\u5b9a\u5728where\u8bed\u53e5\u4e2d\u4f7f\u7528\u7684\u5217\u5b58\u5728\u7d22\u5f15\uff09\u3002\u76f8\u5bf9\u4e8eIN\u5b50\u53e5\u6765\u8bf4\uff0cEXISTS\u4f7f\u7528\u76f8\u8fde\u5b50\u67e5\u8be2\uff0c\u6784\u9020\u8d77\u6765\u8981\u6bd4IN\u5b50\u67e5\u8be2\u56f0\u96be\u4e00\u4e9b\u3002
\u901a\u8fc7\u4f7f\u7528EXIST\uff0cOracle\u7cfb\u7edf\u4f1a\u9996\u5148\u68c0\u67e5\u4e3b\u67e5\u8be2\uff0c\u7136\u540e\u8fd0\u884c\u5b50\u67e5\u8be2\u76f4\u5230\u5b83\u627e\u5230\u7b2c\u4e00\u4e2a\u5339\u914d\u9879\uff0c\u8fd9\u5c31\u8282\u7701\u4e86\u65f6\u95f4\u3002Oracle\u7cfb\u7edf\u5728\u6267\u884cIN\u5b50\u67e5\u8be2\u65f6\uff0c\u9996\u5148\u6267\u884c\u5b50\u67e5\u8be2\uff0c\u5e76\u5c06\u83b7\u5f97\u7684\u7ed3\u679c\u5217\u8868\u5b58\u653e\u5728\u5728\u4e00\u4e2a\u52a0\u4e86\u7d22\u5f15\u7684\u4e34\u65f6\u8868\u4e2d\u3002\u5728\u6267\u884c\u5b50\u67e5\u8be2\u4e4b\u524d\uff0c\u7cfb\u7edf\u5148\u5c06\u4e3b\u67e5\u8be2\u6302\u8d77\uff0c\u5f85\u5b50\u67e5\u8be2\u6267\u884c\u5b8c\u6bd5\uff0c\u5b58\u653e\u5728\u4e34\u65f6\u8868\u4e2d\u4ee5\u540e\u518d\u6267\u884c\u4e3b\u67e5\u8be2\u3002\u8fd9\u4e5f\u5c31\u662f\u4f7f\u7528EXISTS\u6bd4\u4f7f\u7528IN\u901a\u5e38\u67e5\u8be2\u901f\u5ea6\u5feb\u7684\u539f\u56e0\u3002
\u540c\u65f6\u5e94\u5c3d\u53ef\u80fd\u4f7f\u7528NOT EXISTS\u6765\u4ee3\u66ffNOT IN\uff0c\u5c3d\u7ba1\u4e8c\u8005\u90fd\u4f7f\u7528\u4e86NOT\uff08\u4e0d\u80fd\u4f7f\u7528\u7d22\u5f15\u800c\u964d\u4f4e\u901f\u5ea6\uff09\uff0cNOT EXISTS\u8981\u6bd4NOT IN\u67e5\u8be2\u6548\u7387\u66f4\u9ad8\u3002<\/DIV><\/DIV><\/p>\n","protected":false},"excerpt":{"rendered":"
\u63d0\u9ad8mysql\u6027\u80fd\u7684\u65b9\u6cd5! \u6765\u81ea\uff1achinaunix \u4f5c\u8005\uff1auunguymadman007\u98ce\u4e91\u4f7f\u8005 \u4e00\u3001\u95ee\u9898\u7684\u63d0\u51fa\u5728\u5e94\u7528\u7cfb\u7edf\u5f00\u53d1\u521d\u671f\uff0c\u7531\u4e8e\u5f00\u53d1\u6570\u636e\u5e93\u6570\u636e\u6bd4\u8f83\u5c11\uff0c\u5bf9\u4e8e\u67e5\u8be2SQL\u8bed\u53e5\uff0c\u590d\u6742\u89c6\u56fe\u7684\u7684\u7f16\u5199\u7b49\u4f53\u4f1a\u4e0d\u51faSQL\u8bed\u53e5\u5404\u79cd\u5199\u6cd5\u7684\u6027\u80fd\u4f18\u52a3\uff0c\u4f46\u662f\u5982\u679c\u5c06\u5e94\u7528\u7cfb\u7edf\u63d0\u4ea4\u5b9e\u9645\u5e94\u7528\u540e\uff0c\u968f\u7740\u6570\u636e\u5e93\u4e2d\u6570\u636e\u7684\u589e\u52a0\uff0c\u7cfb\u7edf\u7684\u54cd\u5e94\u901f\u5ea6\u5c31\u6210\u4e3a\u76ee\u524d\u7cfb\u7edf\u9700\u8981\u89e3\u51b3\u7684\u6700\u4e3b\u8981\u7684\u95ee\u9898\u4e4b\u4e00\u3002\u7cfb\u7edf\u4f18\u5316\u4e2d\u4e00\u4e2a\u5f88\u91cd\u8981\u7684\u65b9\u9762\u5c31\u662fSQL\u8bed\u53e5\u7684\u4f18\u5316\u3002\u5bf9\u4e8e\u6d77\u91cf\u6570\u636e\uff0c\u52a3\u8d28SQL\u8bed\u53e5\u548c\u4f18\u8d28SQL\u8bed\u53e5\u4e4b\u95f4\u7684\u901f\u5ea6\u5dee\u522b\u53ef\u4ee5\u8fbe\u5230\u4e0a\u767e\u500d\uff0c\u53ef\u89c1\u5bf9\u4e8e\u4e00\u4e2a\u7cfb\u7edf\u4e0d\u662f\u7b80\u5355\u5730\u80fd\u5b9e\u73b0\u5176\u529f\u80fd\u5c31\u53ef\uff0c\u800c\u662f\u8981\u5199\u51fa\u9ad8\u8d28\u91cf\u7684SQL\u8bed\u53e5\uff0c\u63d0\u9ad8\u7cfb\u7edf\u7684\u53ef\u7528\u6027\u3002\u5728\u591a\u6570\u60c5\u51b5\u4e0b\uff0cOracle\u4f7f\u7528\u7d22\u5f15\u6765\u66f4\u5feb\u5730\u904d\u5386\u8868\uff0c\u4f18\u5316\u5668\u4e3b\u8981\u6839\u636e\u5b9a\u4e49\u7684\u7d22\u5f15\u6765\u63d0\u9ad8\u6027\u80fd\u3002\u4f46\u662f\uff0c\u5982\u679c\u5728SQL\u8bed\u53e5\u7684where\u5b50\u53e5\u4e2d\u5199\u7684SQL\u4ee3\u7801\u4e0d\u5408\u7406\uff0c\u5c31\u4f1a\u9020\u6210\u4f18\u5316\u5668\u5220\u53bb\u7d22\u5f15\u800c\u4f7f\u7528\u5168\u8868\u626b\u63cf\uff0c\u4e00\u822c\u5c31\u8fd9\u79cdSQL\u8bed\u53e5\u5c31\u662f\u6240\u8c13\u7684\u52a3\u8d28SQL\u8bed\u53e5\u3002\u5728\u7f16\u5199SQL\u8bed\u53e5\u65f6\u6211\u4eec\u5e94\u6e05\u695a\u4f18\u5316\u5668\u6839\u636e\u4f55\u79cd\u539f\u5219\u6765\u5220\u9664\u7d22\u5f15\uff0c\u8fd9\u6709\u52a9\u4e8e\u5199\u51fa\u9ad8\u6027\u80fd\u7684SQL\u8bed\u53e5\u3002\u4e8c\u3001SQL\u8bed\u53e5\u7f16\u5199\u6ce8\u610f\u95ee\u9898\u4e0b\u9762\u5c31\u67d0\u4e9bSQL\u8bed\u53e5\u7684where\u5b50\u53e5\u7f16\u5199\u4e2d\u9700\u8981\u6ce8\u610f\u7684\u95ee\u9898\u4f5c\u8be6\u7ec6\u4ecb\u7ecd\u3002\u5728\u8fd9\u4e9bwhere\u5b50\u53e5\u4e2d\uff0c\u5373\u4f7f\u67d0\u4e9b\u5217\u5b58\u5728\u7d22\u5f15\uff0c\u4f46\u662f\u7531\u4e8e\u7f16\u5199\u4e86\u52a3\u8d28\u7684SQL\uff0c\u7cfb\u7edf\u5728\u8fd0\u884c\u8be5SQL\u8bed\u53e5\u65f6\u4e5f\u4e0d\u80fd\u4f7f\u7528\u8be5\u7d22\u5f15\uff0c\u800c\u540c\u6837\u4f7f\u7528\u5168\u8868\u626b\u63cf\uff0c\u8fd9\u5c31\u9020\u6210\u4e86\u54cd\u5e94\u901f\u5ea6\u7684\u6781\u5927\u964d\u4f4e\u30021. IS NULL \u4e0e IS NOT NULL\u4e0d\u80fd\u7528null\u4f5c\u7d22\u5f15\uff0c\u4efb\u4f55\u5305\u542bnull\u503c\u7684\u5217\u90fd\u5c06\u4e0d\u4f1a\u88ab\u5305\u542b\u5728\u7d22\u5f15\u4e2d\u3002\u5373\u4f7f\u7d22\u5f15\u6709\u591a\u5217\u8fd9\u6837\u7684\u60c5\u51b5\u4e0b\uff0c\u53ea\u8981\u8fd9\u4e9b\u5217\u4e2d\u6709\u4e00\u5217\u542b\u6709null\uff0c\u8be5\u5217\u5c31\u4f1a\u4ece\u7d22\u5f15\u4e2d\u6392\u9664\u3002\u4e5f\u5c31\u662f\u8bf4\u5982\u679c\u67d0\u5217\u5b58\u5728\u7a7a\u503c\uff0c\u5373\u4f7f\u5bf9\u8be5\u5217\u5efa\u7d22\u5f15\u4e5f\u4e0d\u4f1a\u63d0\u9ad8\u6027\u80fd\u3002\u4efb\u4f55\u5728where\u5b50\u53e5\u4e2d\u4f7f\u7528is null\u6216is not null\u7684\u8bed\u53e5\u4f18\u5316\u5668\u662f\u4e0d\u5141\u8bb8\u4f7f\u7528\u7d22\u5f15\u7684\u30022. \u8054\u63a5\u5217\u5bf9\u4e8e\u6709\u8054\u63a5\u7684\u5217\uff0c\u5373\u4f7f\u6700\u540e\u7684\u8054\u63a5\u503c\u4e3a\u4e00\u4e2a\u9759\u6001\u503c\uff0c\u4f18\u5316\u5668\u662f\u4e0d\u4f1a\u4f7f\u7528\u7d22\u5f15\u7684\u3002\u6211\u4eec\u4e00\u8d77\u6765\u770b\u4e00\u4e2a\u4f8b\u5b50\uff0c\u5047\u5b9a\u6709\u4e00\u4e2a\u804c\u5de5\u8868\uff08employee\uff09\uff0c\u5bf9\u4e8e\u4e00\u4e2a\u804c\u5de5\u7684\u59d3\u548c\u540d\u5206\u6210\u4e24\u5217\u5b58\u653e\uff08FIRST_NAME\u548cLAST_NAME\uff09\uff0c\u73b0\u5728\u8981\u67e5\u8be2\u4e00\u4e2a\u53eb\u6bd4\u5c14.\u514b\u6797\u987f\uff08Bill Cliton\uff09\u7684\u804c\u5de5\u3002\u4e0b\u9762\u662f\u4e00\u4e2a\u91c7\u7528\u8054\u63a5\u67e5\u8be2\u7684SQL\u8bed\u53e5\uff0cselect * from employsswherefirst_name||”||last_name =’Beill Cliton’ \u4e0a\u9762\u8fd9\u6761\u8bed\u53e5\u5b8c\u5168\u53ef\u4ee5\u67e5\u8be2\u51fa\u662f\u5426\u6709Bill Cliton\u8fd9\u4e2a\u5458\u5de5\uff0c\u4f46\u662f\u8fd9\u91cc\u9700\u8981\u6ce8\u610f\uff0c\u7cfb\u7edf\u4f18\u5316\u5668\u5bf9\u57fa\u4e8elast_name\u521b\u5efa\u7684\u7d22\u5f15\u6ca1\u6709\u4f7f\u7528\u3002\u5f53\u91c7\u7528\u4e0b\u9762\u8fd9\u79cdSQL\u8bed\u53e5\u7684\u7f16\u5199\uff0cOracle\u7cfb\u7edf\u5c31\u53ef\u4ee5\u91c7\u7528\u57fa\u4e8elast_name\u521b\u5efa\u7684\u7d22\u5f15\u3002Select * from employeewherefirst_name =’Beill’ and last_name =’Cliton’ \u9047\u5230\u4e0b\u9762\u8fd9\u79cd\u60c5\u51b5\u53c8\u5982\u4f55\u5904\u7406\u5462\uff1f\u5982\u679c\u4e00\u4e2a\u53d8\u91cf\uff08name\uff09\u4e2d\u5b58\u653e\u7740Bill Cliton\u8fd9\u4e2a\u5458\u5de5\u7684\u59d3\u540d\uff0c\u5bf9\u4e8e\u8fd9\u79cd\u60c5\u51b5\u6211\u4eec\u53c8\u5982\u4f55\u907f\u514d\u5168\u7a0b\u904d\u5386\uff0c\u4f7f\u7528\u7d22\u5f15\u5462\uff1f\u53ef\u4ee5\u4f7f\u7528\u4e00\u4e2a\u51fd\u6570\uff0c\u5c06\u53d8\u91cfname\u4e2d\u7684\u59d3\u548c\u540d\u5206\u5f00\u5c31\u53ef\u4ee5\u4e86\uff0c\u4f46\u662f\u6709\u4e00\u70b9\u9700\u8981\u6ce8\u610f\uff0c\u8fd9\u4e2a\u51fd\u6570\u662f\u4e0d\u80fd\u4f5c\u7528\u5728\u7d22\u5f15\u5217\u4e0a\u3002\u4e0b\u9762\u662fSQL\u67e5\u8be2\u811a\u672c\uff1aselect * from employeewherefirst_name = SUBSTR(‘&&name’,1,INSTR(‘&&name’,’ ‘)-1)andlast_name = SUBSTR(‘&&name’,INSTR(‘&&name\u2019,’ ‘)+1) 3. \u5e26\u901a\u914d\u7b26\uff08%\uff09\u7684like\u8bed\u53e5\u540c\u6837\u4ee5\u4e0a\u9762\u7684\u4f8b\u5b50\u6765\u770b\u8fd9\u79cd\u60c5\u51b5\u3002\u76ee\u524d\u7684\u9700\u6c42\u662f\u8fd9\u6837\u7684\uff0c\u8981\u6c42\u5728\u804c\u5de5\u8868\u4e2d\u67e5\u8be2\u540d\u5b57\u4e2d\u5305\u542bcliton\u7684\u4eba\u3002\u53ef\u4ee5\u91c7\u7528\u5982\u4e0b\u7684\u67e5\u8be2SQL\u8bed\u53e5\uff1aselect * from employee where last_name like ‘%cliton%’ \u8fd9\u91cc\u7531\u4e8e\u901a\u914d\u7b26\uff08%\uff09\u5728\u641c\u5bfb\u8bcd\u9996\u51fa\u73b0\uff0c\u6240\u4ee5Oracle\u7cfb\u7edf\u4e0d\u4f7f\u7528last_name\u7684\u7d22\u5f15\u3002\u5728\u5f88\u591a\u60c5\u51b5\u4e0b\u53ef\u80fd\u65e0\u6cd5\u907f\u514d\u8fd9\u79cd\u60c5\u51b5\uff0c\u4f46\u662f\u4e00\u5b9a\u8981\u5fc3\u4e2d\u6709\u5e95\uff0c\u901a\u914d\u7b26\u5982\u6b64\u4f7f\u7528\u4f1a\u964d\u4f4e\u67e5\u8be2\u901f\u5ea6\u3002\u7136\u800c\u5f53\u901a\u914d\u7b26\u51fa\u73b0\u5728\u5b57\u7b26\u4e32\u5176\u4ed6\u4f4d\u7f6e\u65f6\uff0c\u4f18\u5316\u5668\u5c31\u80fd\u5229\u7528\u7d22\u5f15\u3002\u5728\u4e0b\u9762\u7684\u67e5\u8be2\u4e2d\u7d22\u5f15\u5f97\u5230\u4e86\u4f7f\u7528\uff1aselect * from employee where last_name like … Continue reading \u63d0\u9ad8mysql\u6027\u80fd\u7684\u65b9\u6cd5!<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[19],"tags":[203],"class_list":["post-466","post","type-post","status-publish","format-standard","hentry","category-mysql","tag-mysql"],"_links":{"self":[{"href":"https:\/\/www.strongd.net\/index.php?rest_route=\/wp\/v2\/posts\/466","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.strongd.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.strongd.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.strongd.net\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.strongd.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=466"}],"version-history":[{"count":1,"href":"https:\/\/www.strongd.net\/index.php?rest_route=\/wp\/v2\/posts\/466\/revisions"}],"predecessor-version":[{"id":904,"href":"https:\/\/www.strongd.net\/index.php?rest_route=\/wp\/v2\/posts\/466\/revisions\/904"}],"wp:attachment":[{"href":"https:\/\/www.strongd.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=466"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.strongd.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=466"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.strongd.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=466"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}