{"id":863,"date":"2017-11-18T13:48:18","date_gmt":"2017-11-18T05:48:18","guid":{"rendered":"https:\/\/www.beneplot.com\/?p=863"},"modified":"2021-07-15T10:51:54","modified_gmt":"2021-07-15T02:51:54","slug":"sql%e4%bd%bf%e7%94%a8%e8%ae%b0%e5%bd%95","status":"publish","type":"post","link":"https:\/\/www.beneplot.com\/?p=863","title":{"rendered":"SQL\u8bed\u53e5\u8bb0\u5f55"},"content":{"rendered":"

\u5f53\u6570\u636e\u91cf\u8f83\u5c0f\u65f6\uff0c\u4f7f\u7528EXCEL\u5904\u7406\u6570\u636e\u66f4\u65b9\u4fbf\u548c\u9ad8\u6548\u3002<\/span><\/strong><\/p>\n

\u4f46\u82e5\u662f\u6570\u636e\u91cf\u5f88\u5927\uff0c\u6216\u662f\u9700\u8981\u5bf9\u8f83\u591a\u6570\u636e\u8fdb\u884c\u590d\u6742\u7684\u5904\u7406\uff0cSQL\u7684\u6548\u7387\u4fbf\u663e\u73b0\u51fa\u6765\u4e86\u3002<\/span><\/strong><\/p>\n

\u5728\u8fd9\u91cc\u8bb0\u5f55\u5e38\u7528\u7684SQL\u8bed\u53e5\uff0c<\/span><\/strong>\u6211\u7684SQL\u6c34\u5e73\u6bd4\u8f83\u521d\u7ea7\u54c8<\/span><\/strong>\ud83d\ude42<\/span><\/strong><\/h2>\n
\n

 <\/p>\n

\/* \u5c061\u4e2a\u5df2\u6709\u6570\u636e\u8868\u4e2d\u7684\u5168\u90e8\u6570\u636e\u63d0\u53d6\u52301\u4e2a\u65b0\u521b\u5efa\u7684\u8868\u4e2d, \u8868\u7684\u65b0\u5efa\u4e0e\u5907\u4efd<\/strong>*\/<\/div>\n
\u00a0<\/div>\n
CREATE TABLE<\/strong> \u65b0\u8868\u540d AS\u00a0<\/strong><\/code><\/div>\n
SELECT<\/strong> * FROM<\/strong> \u5df2\u6709\u65e7\u8868\u540d<\/code><\/div>\n
\u00a0<\/div>\n
\u00a0<\/div>\n
\/* \u4e0b\u53e5\u4e0e\u4e0a\u53e5\u7684\u7ed3\u679c\u76f8\u540c*\/<\/div>\n
\u00a0<\/div>\n
SELECT *<\/code><\/strong>INTO<\/strong> \u65b0\u8868\u540d<\/code>
\nFROM<\/strong> \u5df2\u6709\u65e7\u8868\u540d;<\/code><\/div>\n
\u00a0<\/div>\n
\n
\u00a0<\/div>\n
\u00a0<\/div>\n
\/*\u5728\u88681\u4e2d\u63d2\u5165\u4e00\u884c\u65b0\u6570\u636e<\/strong>*\/<\/div>\n
\nINSERT INTO<\/strong> \u88681\u540d (\u52171\u540d, \u52172\u540d, \u52173\u540d, \u2026\u2026) VALUES<\/strong> (\u503c1, \u503c2, \u503c3, \u2026\u2026);<\/code><\/div>\n
\u00a0<\/div>\n
\n
\u00a0<\/div>\n
\n
\/*\u5220\u9664\u5217<\/strong>*\/<\/div>\n<\/div>\n
\u00a0<\/div>\n
alter table<\/strong> \u8868\u540d drop column<\/strong> \u5217\u540d<\/code><\/div>\n
\u00a0<\/div>\n
\u00a0<\/div>\n
\/*\u5220\u9664\u884c<\/strong>*\/<\/div>\n
\n
\n
\n
\u00a0<\/div>\n
DELETE FROM<\/strong> \u8868\u540d<\/code><\/div>\n
WHERE<\/strong> \u5217\u540d = \u2018\u8981\u5220\u9664\u884c\u5bf9\u5e94\u7684\u5b57\u6bb5\u2019;<\/code><\/div>\n<\/div>\n
\n
\u00a0<\/div>\n<\/div>\n<\/div>\n
\u00a0<\/div>\n
\n
\/* \u5c063\u4e2a\u5217\u540d\u76f8\u540c\u7684\u8868\u7eb5\u5411\u5408\u62101\u4e2a\u65b0\u8868<\/strong>,\u6bcf\u4e2a\u8868\u7684\u5217\u540d\u548c\u7ed3\u6784\u9700\u76f8\u540c*\/<\/div>\n
\u00a0<\/div>\n
CREATE TABLE<\/strong> \u65b0\u8868\u540d AS<\/strong><\/code><\/div>\n
SELECT<\/strong> * FROM<\/strong> \u88681\u540d\u00a0<\/code><\/div>\n
UNION ALL SELECT<\/strong> * FROM<\/strong> \u88682\u540d\u00a0<\/code><\/div>\n
UNION ALL SELECT<\/strong> * FROM<\/strong> \u88683\u540d<\/code><\/div>\n<\/div>\n
\u00a0<\/div>\n
\/* \u5982\u4e0d\u52a0UNION\u540e\u9762\u7684ALL\uff0c\u5219\u5408\u5e76\u540e\u4f1a\u5220\u9664\u91cd\u590d\u6570\u636e<\/strong>*\/<\/div>\n
\u00a0<\/div>\n
\u00a0<\/div>\n
\/* \u6c42\u4e0d\u540c\u8868\u7684\u4ea4\u96c6<\/strong>\uff0c\u5373\u63d0\u53d6\u88681\u548c\u88682\u5171\u6709\u7684\u5185\u5bb9*\/<\/div>\n
\u00a0<\/div>\n
\n
SELECT<\/strong> * FROM<\/strong> \u88681\u540d\u00a0<\/code><\/div>\n
INTERSECT SELECT<\/strong> * FROM<\/strong> \u88682\u540d\u00a0<\/code><\/div>\n<\/div>\n
\u00a0<\/div>\n
\u00a0<\/div>\n
\n
\/* \u6c42\u4e0d\u540c\u8868\u7684\u5dee\u96c6<\/strong>\uff0c\u5373\u63d0\u53d6\uff1a\u5220\u9664\u88681\u548c\u88682\u5171\u6709\u5185\u5bb9\u540e\u7684\u88681\u5185\u5bb9*\/<\/div>\n
\u00a0<\/div>\n
\n
SELECT<\/strong> * FROM<\/strong> \u88681\u540d\u00a0<\/code><\/div>\n
EXCEPT SELECT<\/strong> * FROM<\/strong> \u88682\u540d\u00a0<\/code><\/div>\n<\/div>\n<\/div>\n
\u00a0<\/div>\n
\u00a0<\/div>\n
\n
\/* \u67e51\u5f20\u8868\u5171\u6709<\/span>\u591a\u5c11\u884c\u6570\u636e<\/strong>*\/<\/span><\/div>\n
\n
\u00a0<\/div>\n
SELECT COUNT<\/strong>(*) FROM<\/strong> \u8868\u540d<\/code><\/div>\n<\/div>\n
\u00a0<\/div>\n
\n
\n
SELECT CEILING<\/strong>(1.1)\u00a0<\/code> \/* \u5411\u4e0a\u53d6\u6574<\/strong>\uff0c\u8fd4\u56de2*\/<\/span><\/div>\n<\/div>\n
\u00a0<\/div>\n
SELECT FLOOR<\/strong>(1.9)\u00a0<\/code> \/* \u5411\u4e0b\u53d6\u6574<\/strong>\uff0c\u8fd4\u56de1*\/<\/span><\/div>\n
\u00a0<\/div>\n
SELECT round<\/strong>(1.567,0)\u00a0<\/code> \/* \u56db\u820d\u4e94\u5165\u53d6\u6574<\/strong>\uff0c\u8fd4\u56de2*\/<\/span><\/div>\n
\n
\u00a0<\/div>\n
\u00a0<\/div>\n
\n
\/* \u5c06\u4e0d\u540c\u7684\u8868\u4f9d\u636e\u76f8\u540c\u7684\u884c\u540d\u6a2a\u5411\u5408\u62101\u4e2a\u65b0\u8868, \u7c7b\u4f3cexcel\u7684vlookup\u51fd\u6570<\/strong>*\/<\/div>\n
\u00a0<\/div>\n
CREATE TABLE<\/strong> \u65b0\u8868\u540d AS<\/strong><\/code><\/div>\n
SELECT * FROM<\/strong> \u88681\u540d AS<\/strong> \u88681\u522b\u540d<\/code><\/div>\n
LEFT OUTER JOIN<\/strong> \u88682\u540d AS<\/strong> \u88682\u522b\u540d\u00a0<\/code><\/div>\n
ON<\/strong> (\u88681\u522b\u540d.\u4e0e\u88682\u5185\u5bb9\u5339\u914d\u7684\u5217\u540d = \u88682\u522b\u540d.\u4e0e\u88681\u5185\u5bb9\u5339\u914d\u7684\u5217\u540d);<\/code><\/div>\n<\/div>\n
\u00a0<\/div>\n
\/*\u5982\u679c\u4f7f\u7528INNER JOIN<\/strong> \u66ff\u6362 OUTER JOIN ,\u5219\u63d0\u53d6\u7ed3\u679c\u4e3a\u4e24\u4e2a\u8868\u4e2d\u5171\u6709\u7684\u5185\u5bb9\uff0c\u4e0d\u4f1a\u51fa\u73b0NULL\u503c*\/<\/div>\n
\n
\u00a0<\/div>\n
\/* \u4f7f\u7528 RIGHT <\/b>\u65f6FROM \u5b50\u53e5\u4e2d\u5199\u5728\u53f3\u4fa7\u7684\u8868\u662f\u4e3b\u8868*\/<\/div>\n<\/div>\n
\u00a0<\/div>\n
\n
\u00a0<\/div>\n
\u00a0<\/div>\n
\n
\/* to_char\u51fd\u6570\u4e0eCAST\u51fd\u6570<\/strong>*\/<\/div>\n
\u00a0<\/div>\n
\u00a0<\/div>\n
\/*\u5c06\u539f\u6709\u503c(\u975e\u5b57\u7b26\u4e32)\u8f6c\u6362\u6210\u81ea\u5b9a\u4e49\u683c\u5f0f\u7684\u5b57\u7b26\u4e32\u7c7b\u578b*\/<\/div>\n
\u00a0<\/div>\n
SELECT to_char<\/strong>( \u5217\u540d, '\u81ea\u5b9a\u4e49\u683c\u5f0f' ) FROM<\/strong> \u8868\u540d<\/code><\/div>\n
\u00a0<\/div>\n
\/* \u4e0b\u4f8b\u5c06\u65f6\u95f4\u683c\u5f0f\u8f6c\u6362\u4e3a\u4ec5\u663e\u793a\u5e74\u6708\u7684\u5b57\u7b26\u4e32\u683c\u5f0f, \u5982\u5c062020-01-01\u8f6c\u4e3a ‘2020-01’ *\/<\/div>\n
\u00a0<\/div>\n
SELECT to_char<\/strong>(time, 'YYYY-MM' ) FROM<\/strong> \u8868\u540d<\/code><\/div>\n
\u00a0<\/div>\n
\/* CAST(\u8f6c\u6362\u524d\u7684\u503c AS \u60f3\u8981\u8f6c\u6362\u7684\u6570\u636e\u7c7b\u578b),\u4e0b\u4f8b\u662f\u5c06\u5b57\u7b26\u4e32\u65e5\u671f\u8f6c\u6362\u4e3a\u65e5\u671f\u7c7b\u578b, \u8868\u9762\u770b\u4e0d\u51fa\u5dee\u522b*\/<\/div>\n
\u00a0<\/div>\n
SELECT CAST<\/strong>(\u5217\u540d AS DATE<\/strong> ) FROM<\/strong> \u8868\u540d<\/code><\/div>\n<\/div>\n
\n
\u00a0<\/div>\n
\u00a0<\/div>\n
\n
\/*COALESCE \u2014 \u5c06NULL\u8f6c\u6362\u4e3a\u5176\u4ed6\u503c<\/strong>*\/<\/div>\n
\u00a0<\/div>\n
\/*\u628a\u88681\u7684\u52171\u4e2d\u7684\u7a7a\u503cNULL\u5168\u90e8\u8f6c\u4e3aXXX *\/<\/div>\n
\u00a0<\/div>\n
UPDATE<\/strong> \u88681\u540d\u00a0<\/code><\/div>\n
SET<\/strong> \u52171\u540d = COALESCE<\/strong>(\u52171\u540d, 'XXX')<\/code><\/div>\n
\u00a0<\/div>\n
\u6216\u662f\uff1a<\/div>\n
SELECT COALESCE<\/strong>(\u52171\u540d, 'XXX')<\/code>FROM<\/strong> \u88681\u540d<\/code><\/div>\n<\/div>\n
\n

 <\/p>\n

\n
\/*\u63d0\u53d6\u88681\u524d5\u884c\u7684\u6570\u636e<\/strong>*\/<\/div>\n
\u00a0<\/div>\n
SELECT<\/strong> * FROM<\/strong> \u88681\u540d<\/code><\/div>\n
limit<\/strong> 5<\/code><\/div>\n<\/div>\n
\n
\u00a0<\/div>\n
\n
\u00a0<\/div>\n
\/*\u63d0\u53d6\u88681\u7684\u6240\u6709\u5217\u540d<\/strong>*\/<\/div>\n
\u00a0<\/div>\n
select column_name<\/code><\/strong><\/div>\n
from information_schema.columns\u00a0<\/code><\/strong><\/div>\n
where table_name<\/strong> = '\u88681\u540d';<\/code><\/div>\n<\/div>\n
\n
\u00a0<\/div>\n
\u00a0<\/div>\n
\n
\/*\u4e0b\u8bed\u53e5\u7684\u610f\u601d\u662f\uff1a\u4ece\u88681\u4e2d\u63d0\u53d63\u5217\u6570\u636e,<\/div>\n
\u00a0<\/div>\n
\u63d0\u53d6\u51fa\u7684\u6570\u636e\u4ee5\u52173\u964d\u5e8f\u6392\u5217(\u4e0d\u52a0DESC\u5219\u4f1a\u4ee5\u5347\u5e8f\u6392\u5217)<\/strong>,<\/div>\n
\u00a0<\/div>\n
\u5e76\u4e14\u8fd9\u4e9b\u6570\u636e\u9700\u540c\u65f6\u6ee1\u8db32\u4e2a\u6761\u4ef6<\/strong>\uff1a\u52171=XX\u548c\u52172=1\u3002<\/div>\n
\u00a0<\/div>\n
\u6709\u65f6\u5019\u56e0\u4e3a\u67d0\u4e9b\u683c\u5f0f\u9650\u5236,\u773c\u89c1\u662fXX,\u4f46\u8f93\u5165XX\u5374\u63d0\u53d6\u4e0d\u51fa\u6570\u636e,<\/div>\n
\u00a0<\/div>\n
\u56e0\u6b64\u53ef\u5c1d\u8bd5\u4f7f\u7528\u201cLIKE ‘%XX%’\u201d\u6765\u63d0\u53d6XX\u6570\u636e*\/<\/div>\n
\u00a0<\/div>\n
SELECT<\/strong> \u52171\u540d, \u52172\u540d, \u52173\u540d\u00a0 FROM<\/strong> \u88681\u540d\u00a0<\/code><\/div>\n
where<\/strong> \u5217\u540d1 LIKE<\/strong> '%XX%' AND<\/strong> \u52172\u540d = 1<\/code><\/div>\n
ORDER BY<\/strong> \u52173\u540d DESC<\/strong>;<\/code><\/div>\n
\u00a0<\/div>\n
\u00a0<\/div>\n
\/* LIKE\u4f7f\u7528\u8bf4\u660e<\/strong>*\/<\/div>\n
\u00a0<\/div>\n
\u00a0LIKE<\/strong> 'XX%' \u4f1a\u5c06\u4ee5XX\u5f00\u5934\u7684\u6570\u636e\u63d0\u53d6\u51fa\u6765,\u5982XXYY,XX123\uff1b<\/code><\/div>\n
\u00a0LIKE<\/strong> '%XX' \u4f1a\u5c06\u4ee5XX\u7ed3\u5c3e\u7684\u6570\u636e\u63d0\u53d6\u51fa\u6765,\u5982YYXX,123XX\uff1b<\/code><\/div>\n
\u00a0LIKE<\/strong> '%XX%' \u4f1a\u5c06\u542b\u6709XX\u7684\u6240\u6709\u6570\u636e\u63d0\u53d6\u51fa\u6765\u3002<\/code><\/div>\n<\/div>\n

 <\/p>\n

\n
\u00a0<\/div>\n
\n
\/*\u4e0b\u8bed\u53e5\u7684\u610f\u601d\u662f\uff1a\u4ece\u88681\u4e2d\u63d0\u53d64\u5217\u6570\u636e,<\/div>\n
\u00a0<\/div>\n
\u8fd9\u4e9b\u6570\u636e\u9700\u540c\u65f6\u6ee1\u8db32\u4e2a\u6761\u4ef6\uff1a\u52175=1\u548c\u52176=2,<\/div>\n
\u00a0<\/div>\n
\u63d0\u53d6\u51fa\u7684\u6570\u636e\u4f1a\u5220\u9664\u91cd\u590d\u7684\u52172\u3001\u52173\u3001\u52174\u7ec4\u5408<\/strong>,<\/div>\n
\u00a0<\/div>\n
\u63d0\u53d6\u51fa\u7684\u52171\u53d8\u6210\u8ba1\u6570\u5217, \u5373\u5728\u67d0\u4e2a\u52172\u3001\u52173\u3001\u52174\u7ec4\u5408\u4e0b,\u52171\u4e2d\u5305\u542b\u7684\u4e0e\u4e4b\u76f8\u5bf9\u5e94\u7684\u7684\u6570\u636e\u91cf<\/strong>\u3002<\/div>\n
\u00a0<\/div>\n
\u4f8b\u5b50\uff1a\u5047\u8bbe\u52172\u662f\u65f6\u95f4\u3001\u52173\u662f\u59d3\u540d\u3001\u52174\u5730\u70b9,\u201c2020.1\u6708\/\u5f20\u4e09\/\u5728\u4f53\u80b2\u573a\u201d\u6784\u6210\u4e86\u4e00\u4e2a\u7ec4\u5408,<\/div>\n
\u00a0<\/div>\n
\u5047\u5982\u52171\u662f\u4e8b\u4ef6,\u5982\u679c\u201d\u57282020.1\u6708\u5185,\u5f20\u4e09\u5728\u4f53\u80b2\u573a\u201c\u8fdb\u884c\u4e86\u8dd1\u6b65\u3001\u6253\u7bee\u7403\u3001\u8e22\u8db3\u7403\u4e09\u6b21\u8fd0\u52a8,<\/div>\n
\u00a0<\/div>\n
count\u7684\u8ba1\u7b97\u7ed3\u679c\u662f3\u3002*\/<\/div>\n
\u00a0<\/div>\n
CREATE TABLE<\/strong> \u88682\u540d AS<\/strong><\/code><\/div>\n
select count<\/strong>(\u52171\u540d), \u52172\u540d, \u52173\u540d, \u52174\u540d from<\/strong> \u88681\u540d\u00a0<\/code><\/div>\n
where<\/strong> \u52175\u540d = 1 AND<\/strong> \u52176\u540d = 2<\/code><\/div>\n
GROUP BY<\/strong> \u52172\u540d, \u52173\u540d, \u52174\u540d<\/code><\/div>\n<\/div>\n
\u00a0<\/div>\n
\n
\u00a0<\/div>\n
\/*\u4e0a\u9762\u7684\u7ed3\u679c\u544a\u8bc9\u6211\u4eec\uff1a\u67d0\u4eba\u5728\u67d0\u5730\u5728\u67d0\u65f6\u95f4\u6bb5\u5185\u505a\u4e86\u51e0\u4ef6\u4e8b,<\/div>\n
\u00a0<\/div>\n
\u63a5\u4e0b\u6765\u5982\u679c\u60f3\u77e5\u9053\uff1a\u5728\u6240\u6709\u65f6\u95f4\u6bb5\u5185,\u67d0\u4eba\u5728\u67d0\u5730\u505a\u4e86\u51e0\u4ef6\u4e8b,<\/div>\n
\u00a0<\/div>\n
\u4ecd\u65e7\u5047\u8bbe\u52173\u662f\u59d3\u540d\u3001\u52174\u5730\u70b9,<\/div>\n
\u00a0<\/div>\n
\u53ef\u4ee5\u5728\u4e0a\u9762\u63d0\u53d6\u7ed3\u679c\u7684\u88682\u4e0a\u518d\u6b21\u63d0\u53d6\u6570\u636e\u3002*\/<\/div>\n
\u00a0<\/div>\n
select count<\/strong>(\u5217\u540d3), \u5217\u540d3, \u5217\u540d4 from<\/strong> \u88682\u540d GROUP BY<\/strong> \u52173\u540d, \u52174\u540d<\/code><\/div>\n<\/div>\n
\u00a0<\/div>\n
\n
\u00a0<\/div>\n
\/*\u4ee5\u4e0a2\u4e2a\u8bed\u53e5\u53ef\u7ec4\u5408\u4e3a1\u4e2a*\/<\/div>\n
\u00a0<\/div>\n
select count<\/strong>(\u5217\u540d3), \u5217\u540d3, \u5217\u540d4<\/code><\/div>\n
from<\/code><\/strong><\/div>\n
(select count<\/strong>(\u52171\u540d), \u52172\u540d, \u52173\u540d, \u52174\u540d from<\/strong> \u88681\u540d\u00a0<\/code><\/div>\n
where<\/strong> \u52175\u540d = 1 AND<\/strong> \u52176\u540d = 2<\/code><\/div>\n
GROUP BY<\/strong> \u52172\u540d, \u52173\u540d, \u52174\u540d) AS<\/strong> \u88682\u540d<\/code><\/div>\n
GROUP BY<\/strong> \u52173\u540d, \u52174\u540d<\/code><\/div>\n
\u00a0<\/div>\n
\/*\u4e0a\u9762\u8fd9\u4e2a\u8bed\u53e5\u548c\u4e0b\u9762\u8fd9\u4e2a\u8bed\u53e5\u7684\u76f8\u540c\u70b9\u662f\uff1a\u5b83\u4eec\u63d0\u53d6\u7684\u7ed3\u679c\u884c\u6570\u76f8\u540c,\u63d0\u53d6\u7684\u52173\u548c\u52174\u4e5f\u76f8\u540c\uff1b<\/div>\n
\u00a0<\/div>\n
\u4e0d\u540c\u70b9\u662f\uff1a\u5982\u679c\u57282020.1\u6708(\u540c\u4e00\u65f6\u95f4\u6bb5),\u5f20\u4e09\u6253\u4e86\u4e24\u6b21\u7bee\u7403,<\/div>\n
\u00a0<\/div>\n
\u4e0a\u4e00\u53e5\u4f1a\u8bb0\u5f551\u6b21(\u5176\u4e2d1\u4e2aGROUP BY\u7528\u4e8e\u5220\u9664<\/strong>\u540c\u4e00\u65f6\u95f4\u7684\u91cd\u590d\u503c<\/strong>),<\/div>\n
\u00a0<\/div>\n
\u4e0b\u4e00\u53e5\u4f1a\u8bb0\u5f552\u6b21*\/<\/div>\n
\u00a0<\/div>\n
select count<\/strong>(\u5217\u540d1), \u5217\u540d3, \u5217\u540d4 from<\/strong> \u88681\u540d\u00a0<\/code><\/div>\n
where<\/strong> \u5217\u540d5 = 1 AND<\/strong> \u5217\u540d6 = 2<\/code><\/div>\n
GROUP BY<\/strong> \u5217\u540d3, \u5217\u540d4<\/code><\/div>\n<\/div>\n
\n
\n
\u00a0<\/div>\n
\/*\u4f7f\u7528DISTINCT\u53ef\u5220\u9664\u5217\u4e2d\u91cd\u590d\u7684\u6570\u636e<\/strong>*\/<\/div>\n
\u00a0<\/div>\n
SELECT DISTINCT<\/strong> \u5217\u540d FROM<\/strong> \u8868\u540d;<\/code><\/div>\n
\u00a0<\/div>\n
\/*\u4e0b\u8bed\u53e5\u548c\u4e0a\u8bed\u53e5\u4f1a\u5f97\u5230\u540c\u6837\u7684\u7ed3\u679c, \u5982\u4e0a\u6240\u8ff0, GROUP BY\u4e5f\u6709\u5220\u9664\u91cd\u590d\u6570\u636e\u7684\u4f5c\u7528<\/strong>*\/<\/div>\n
\u00a0<\/div>\n
SELECT<\/strong> \u5217\u540d FROM<\/strong> \u8868\u540d<\/code><\/div>\n
GROUP BY<\/strong> \u5217\u540d;<\/code><\/div>\n<\/div>\n
\u00a0<\/div>\n
\u00a0<\/div>\n
\n
\/*\u4e0b\u8bed\u53e5\u4f1a\u5220\u9664\u52171\u548c\u52172\u7ec4\u5408\u540e\u7684\u91cd\u590d\u6570\u636e<\/strong>*\/<\/div>\n
\u00a0<\/div>\n
SELECT DISTINCT<\/strong> \u52171\u540d, \u52172\u540d<\/code><\/div>\n
FROM<\/strong> \u8868\u540d;<\/code><\/div>\n<\/div>\n
\u00a0<\/div>\n
\u00a0<\/div>\n
\n
\u00a0<\/div>\n
\/*\u5c06\u4e24\u5217\u5185\u5bb9\u5408\u6210\u4e3a\u4e00\u5217<\/strong>* \/<\/div>\n
\u00a0<\/div>\n
\/*\u63d0\u53d6\u4e24\u5217\u6570\u636e* \/<\/div>\n
\u00a0<\/div>\n
select e.last_name , e.first_name <\/code>
\nfrom name AS e<\/code><\/div>\n
\u00a0<\/div>\n
\/*\u63d0\u53d61\u5217\u6570\u636e\uff0c\u4ee5\u5355\u5f15\u53f7’\u4e3a\u5206\u9694(\u5728psql\u4e2d\uff0c\u8981\u663e\u793a\u5355\u5f15\u53f7’\u9700\u8981\u952e\u5165\u4e24\u4e2a\u5355\u5f15\u53f7”)\uff0c||<\/code>\u610f\u4e3a\u5408\u5e76\u6570\u636e<\/strong>* \/<\/div>\n
select<\/strong> e.last_name ||<\/strong>''''||<\/strong> e.first_name as name<\/code>
\nfrom name e<\/code><\/div>\n
\u00a0<\/div>\n
\n
\/*\u89e6\u53d1\u5668\u8bbe\u7f6e* \/<\/strong><\/div>\n
\u00a0<\/div>\n
\/*\u5f53\u67d0\u4e2a\u8868\u53d1\u751f\u67d0\u4e8b\u4ef6\u65f6\uff08INSERT\u3001UPDATE\u3001DELETE\u7b49\uff09\uff0c\u5176\u4ed6\u5de5\u4f5c\u8868\u4f1a\u76f8\u5e94\u53d1\u751f\u6539\u53d8*\/<\/div>\n
\u00a0<\/div>\n
\/*psql\u4e2d\u7684\u89e6\u53d1\u5668\u8bbe\u5b9a*\/<\/div>\n
\u00a0<\/div>\n
\n
\/*\u521b\u5efa\u4e24\u4e2a\u8868*\/<\/div>\n
\u00a0<\/div>\n
drop table if exists test1;<\/code><\/div>\n
drop table if exists test2;<\/code><\/div>\n
\u00a0<\/div>\n
CREATE TABLE test1(<\/code><\/div>\n
\u00a0 \u00a0ID INT PRIMARY KEY\u00a0 \u00a0 \u00a0NOT NULL,<\/code><\/div>\n
\u00a0 \u00a0NAME\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0TEXT\u00a0 \u00a0 NOT NULL,<\/code><\/div>\n
\u00a0 \u00a0AGE\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 INT\u00a0 \u00a0 \u00a0NOT NULL,<\/code><\/div>\n
\u00a0 \u00a0ADDRESS\u00a0 \u00a0 \u00a0 \u00a0 CHAR(50)<\/code><\/div>\n
);<\/code><\/div>\n
\u00a0<\/div>\n
CREATE TABLE test2(<\/code><\/div>\n
\u00a0 \u00a0 Num INT NOT NULL,<\/code><\/div>\n
\u00a0 \u00a0 NAME TEXT NOT NULL<\/code><\/div>\n
);<\/code><\/div>\n
\u00a0<\/div>\n
\/*\u9996\u5148\u9700\u8981\u521b\u5efa\u89e6\u53d1\u5668\u51fd\u6570*\/<\/div>\n
\u00a0<\/div>\n
CREATE OR REPLACE FUNCTION tfun() RETURNS TRIGGER AS $trigger1$<\/code><\/div>\n
\u00a0 \u00a0BEGIN<\/code><\/div>\n
\u00a0 \u00a0 \u00a0 INSERT INTO test2 VALUES (new.ID, new.name);<\/code><\/div>\n
\u00a0 \u00a0 \u00a0 RETURN NEW;<\/code><\/div>\n
\u00a0 \u00a0END;<\/code><\/div>\n
$trigger1$ LANGUAGE plpgsql;<\/code><\/div>\n
\u00a0<\/div>\n
\/*\u521b\u5efa\u89e6\u53d1\u5668\uff0c\u6ce8\u610f\uff01\u89e6\u53d1\u5668\u540d\u5e94\u4e0e\u8868\u540d\u6709\u8054\u7cfb\uff0c\u65b9\u4fbf\u540e\u671f\u67e5\u627e*\/<\/div>\n
\u00a0<\/div>\n
CREATE TRIGGER trigger_test1\u00a0<\/code><\/div>\n
\u00a0 \u00a0AFTER INSERT ON test1 FOR EACH ROW\u00a0<\/code><\/div>\n
EXECUTE PROCEDURE tfun();<\/code><\/div>\n
\u00a0<\/div>\n
\/*\u89e6\u53d1\u5668\u68c0\u9a8c\uff0c\u5728test1\u8868\u4e2d\u63d2\u5165\u4fe1\u606f\u65f6\uff0cID\u548cNAME\u4f1a\u81ea\u52a8\u6dfb\u8865\u5230test2\u8868\u4e2d*\/<\/div>\n
\u00a0<\/div>\n
INSERT INTO test1 (ID,NAME,AGE,ADDRESS)VALUES (1, 'Bene', 18, 'China' );<\/code><\/div>\n
select * from test1;<\/code><\/div>\n
select * from test2;<\/code><\/div>\n<\/div>\n
\u00a0<\/div>\n
\u00a0<\/div>\n
\n
\/*\u67e5\u627e\u6570\u636e\u5e93\u4e2d\u5df2\u6709\u7684\u89e6\u53d1\u5668*\/<\/div>\n
SELECT * FROM pg_trigger;<\/code><\/div>\n
\u00a0<\/div>\n
\/*\u5220\u9664\u89e6\u53d1\u5668\uff0cDROP TRIGGER \u89e6\u53d1\u5668\u540d on \u6240\u5728\u8868\u540d<\/code>*\/<\/div>\n
DROP TRIGGER trigger_test1 on test1;<\/code><\/div>\n<\/div>\n
\u00a0<\/div>\n
\n

\/*\u8ba1\u7b97\u4e00\u4e32\u5b57\u7b26\u4e2d\u6709\u51e0\u4e2a\u9017\u53f7<\/strong>*\/<\/p>\n

SELECT LENGTH('i,10ve,y0u')-LENGTH(e) FROM <\/code>
\n(SELECT REPLACE ('i,10ve,y0u',',','')AS e) AS a<\/code><\/div>\n
\n

\/*\u4ee5\u59d3\u540d\u6700\u540e\u4e24\u4e2a\u5b57\u6bcd\u8fdb\u884c\u6392\u5e8f*<\/strong>\/<\/strong><\/p>\n

\/*\u4f7f\u7528substring<\/code>\uff0c'..$'<\/code> \u4e2d\u4e24\u4e2a\u70b9\u4ee3\u8868\u4e24\u4e2a\u5b57\u6bcd\uff0c\u7b26\u53f7$\u8868\u793a\u4ece\u6700\u540e\u5f00\u59cb\u8ba1\u7b97*\/<\/div>\n
\u00a0<\/div>\n
SELECT first_name FROM<\/code>
\n(SELECT first_name,substring(first_name,'..$' ) AS e FROM name<\/code>
\nORDER BY e,first_name) AS c<\/code><\/div>\n
\u00a0<\/div>\n
\u00a0<\/div>\n
\n
\/*\u4f7f\u7528RIGHT<\/code>*\/<\/div>\n
\u00a0<\/div>\n<\/div>\n
SELECT first_name FROM name ORDER BY RIGHT(first_name,2);<\/code><\/div>\n
\u00a0<\/div>\n
\u00a0<\/div>\n
\n
\u00a0<\/div>\n
To be continued…<\/div>\n
\u00a0<\/div>\n","protected":false},"excerpt":{"rendered":"

\u5f53\u6570\u636e\u91cf\u8f83\u5c0f\u65f6\uff0c\u4f7f\u7528EXCEL\u5904\u7406\u6570\u636e\u66f4\u65b9\u4fbf\u548c\u9ad8\u6548\u3002 \u4f46\u82e5\u662f\u6570\u636e\u91cf\u5f88\u5927\uff0c\u6216\u662f\u9700\u8981\u5bf9\u8f83\u591a\u6570\u636e\u8fdb\u884c\u590d\u6742\u7684\u5904\u7406\uff0cSQ […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[10],"tags":[],"yoast_head":"\n\n\n\n\n\n\n\n\n\n\n\n\n\n