{"id":159987,"date":"2024-11-03T19:20:48","date_gmt":"2024-11-03T11:20:48","guid":{"rendered":"https:\/\/server.hk\/cnblog\/159987\/"},"modified":"2024-11-03T19:20:49","modified_gmt":"2024-11-03T11:20:49","slug":"mssql-%e6%95%99%e7%a8%8b-sql-mid-%e5%87%bd%e6%95%b8","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/159987\/","title":{"rendered":"MSSQL \u6559\u7a0b SQL MID() \u51fd\u6578"},"content":{"rendered":"<h1 id=\"mssql-%e6%95%99%e7%a8%8b%ef%bc%9a%e6%b7%b1%e5%85%a5%e8%a7%a3%e6%9e%90-sql-mid-%e5%87%bd%e6%95%b8-xvvOsvYhjE\">MSSQL \u6559\u7a0b\uff1a\u6df1\u5165\u89e3\u6790 SQL MID() \u51fd\u6578<\/h1>\n<p>\u5728\u8655\u7406\u6578\u64da\u5eab\u67e5\u8a62\u6642\uff0c\u5c0d\u5b57\u7b26\u4e32\u7684\u64cd\u4f5c\u662f\u4e0d\u53ef\u6216\u7f3a\u7684\u4e00\u90e8\u5206\u3002Microsoft SQL Server\uff08MSSQL\uff09\u63d0\u4f9b\u4e86\u591a\u7a2e\u5b57\u7b26\u4e32\u51fd\u6578\uff0c\u4ee5\u652f\u6301\u8907\u96dc\u7684\u6578\u64da\u8655\u7406\u9700\u6c42\u3002\u672c\u6587\u5c07\u91cd\u9ede\u4ecb\u7d39 <code>MID()<\/code> \u51fd\u6578\u5728 SQL Server \u4e2d\u7684\u61c9\u7528\uff0c\u900f\u904e\u5be6\u4f8b\u6df1\u5165\u89e3\u6790\u5176\u7528\u6cd5\u548c\u5be6\u969b\u64cd\u4f5c\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af-mid-%e5%87%bd%e6%95%b8%ef%bc%9f-xvvOsvYhjE\">\u4ec0\u9ebc\u662f MID() \u51fd\u6578\uff1f<\/h2>\n<p>MSSQL \u4e2d\u4e26\u6c92\u6709\u76f4\u63a5\u540d\u70ba <code>MID()<\/code> \u7684\u51fd\u6578\uff0c\u9019\u662f\u5728\u5176\u4ed6\u4e00\u4e9b\u6578\u64da\u5eab\u7cfb\u7d71\u5982 MySQL \u4e2d\u7528\u65bc\u63d0\u53d6\u5b57\u7b26\u4e32\u4e2d\u7684\u4e00\u90e8\u5206\u7684\u51fd\u6578\u3002\u5728 SQL Server \u4e2d\uff0c\u76f8\u5c0d\u61c9\u7684\u51fd\u6578\u662f <code>SUBSTRING()<\/code>\u3002 <code>SUBSTRING()<\/code> \u51fd\u6578\u7528\u65bc\u5f9e\u5b57\u7b26\u4e32\u4e2d\u63d0\u53d6\u5b50\u4e32\u3002\u5176\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre>\nSUBSTRING(expression, start, length)\n<\/pre>\n<ul>\n<li><code>expression<\/code>\uff1a\u8981\u5f9e\u4e2d\u63d0\u53d6\u5b50\u4e32\u7684\u5b57\u7b26\u4e32\u8868\u9054\u5f0f\u3002<\/li>\n<li><code>start<\/code>\uff1a\u5b50\u4e32\u958b\u59cb\u4f4d\u7f6e\u7684\u6578\u5b57\u3002<\/li>\n<li><code>length<\/code>\uff1a\u8981\u63d0\u53d6\u7684\u5b57\u7b26\u6578\u3002<\/li>\n<\/ul>\n<h2 id=\"%e5%a6%82%e4%bd%95%e4%bd%bf%e7%94%a8-substring-%e5%87%bd%e6%95%b8-xvvOsvYhjE\">\u5982\u4f55\u4f7f\u7528 SUBSTRING() \u51fd\u6578<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u4e9b\u4f7f\u7528 <code>SUBSTRING()<\/code> \u51fd\u6578\u7684\u5be6\u4f8b\uff0c\u9019\u4e9b\u4f8b\u5b50\u5c07\u5e6b\u52a9\u60a8\u7406\u89e3\u5982\u4f55\u5728\u5be6\u969b\u60c5\u6cc1\u4e2d\u61c9\u7528\u9019\u4e00\u51fd\u6578\u3002<\/p>\n<h3 id=\"%e5%9f%ba%e6%9c%ac%e7%a4%ba%e4%be%8b-xvvOsvYhjE\">\u57fa\u672c\u793a\u4f8b<\/h3>\n<pre>\nSELECT SUBSTRING('Hello World', 1, 5) AS ExtractString;\n<\/pre>\n<p>\u9019\u500b\u67e5\u8a62\u5c07\u8fd4\u56de &#8216;Hello&#8217;\uff0c\u56e0\u70ba\u5b83\u5f9e\u7b2c1\u4f4d\u958b\u59cb\u63d0\u53d6\u4e865\u500b\u5b57\u7b26\u3002<\/p>\n<h3 id=\"%e5%be%9e%e7%89%b9%e5%ae%9a%e4%bd%8d%e7%bd%ae%e9%96%8b%e5%a7%8b%e6%8f%90%e5%8f%96-xvvOsvYhjE\">\u5f9e\u7279\u5b9a\u4f4d\u7f6e\u958b\u59cb\u63d0\u53d6<\/h3>\n<pre>\nSELECT SUBSTRING('SQL Server', 5, 6) AS ExtractString;\n<\/pre>\n<p>\u6b64\u67e5\u8a62\u8fd4\u56de &#8216;Server&#8217;\u3002\u9019\u88e1\uff0c\u63d0\u53d6\u5f9e\u5b57\u7b26\u4e32\u7684\u7b2c5\u500b\u5b57\u7b26\u958b\u59cb\uff0c\u4e26\u6301\u7e8c6\u500b\u5b57\u7b26\u3002<\/p>\n<h3 id=\"%e7%b5%90%e5%90%88%e5%85%b6%e4%bb%96%e5%87%bd%e6%95%b8%e4%bd%bf%e7%94%a8-xvvOsvYhjE\">\u7d50\u5408\u5176\u4ed6\u51fd\u6578\u4f7f\u7528<\/h3>\n<pre>\nSELECT SUBSTRING(FirstName, 1, 3) AS ShortName\nFROM Employees;\n<\/pre>\n<p>\u9019\u500b\u67e5\u8a62\u793a\u4f8b\u5f9e\u54e1\u5de5\u8868\u4e2d\u7684 <code>FirstName<\/code> \u5b57\u6bb5\u63d0\u53d6\u6bcf\u500b\u540d\u5b57\u7684\u524d\u4e09\u500b\u5b57\u6bcd\u3002<\/p>\n<h2 id=\"%e9%ab%98%e7%b4%9a%e6%87%89%e7%94%a8-xvvOsvYhjE\">\u9ad8\u7d1a\u61c9\u7528<\/h2>\n<p><code>SUBSTRING()<\/code> \u51fd\u6578\u4e0d\u50c5\u9650\u65bc\u7c21\u55ae\u7684\u5b57\u7b26\u4e32\u63d0\u53d6\uff0c\u5b83\u53ef\u4ee5\u8207\u5176\u4ed6 SQL \u51fd\u6578\u7d50\u5408\u4f7f\u7528\uff0c\u4ee5\u5be6\u73fe\u66f4\u8907\u96dc\u7684\u6578\u64da\u8655\u7406\u3002\u4f8b\u5982\uff0c\u60a8\u53ef\u4ee5\u4f7f\u7528 <code>LEN()<\/code> \u51fd\u6578\u4f86\u52d5\u614b\u78ba\u5b9a\u63d0\u53d6\u7684\u5b57\u7b26\u4e32\u9577\u5ea6\u3002<\/p>\n<pre>\nSELECT SUBSTRING(Description, 1, LEN(Description) - 3) AS ModifiedDescription\nFROM Products;\n<\/pre>\n<p>\u6b64\u67e5\u8a62\u5f9e\u7522\u54c1\u63cf\u8ff0\u4e2d\u522a\u9664\u6700\u5f8c\u4e09\u500b\u5b57\u7b26\uff0c\u5c55\u793a\u4e86\u5982\u4f55\u7d50\u5408\u4f7f\u7528 <code>LEN()<\/code> \u548c <code>SUBSTRING()<\/code> \u51fd\u6578\u3002<\/p>\n<h2 id=\"%e7%b8%bd%e7%b5%90-xvvOsvYhjE\">\u7e3d\u7d50<\/h2>\n<p>\u4e86\u89e3\u5982\u4f55\u5728 MSSQL \u4e2d\u6709\u6548\u4f7f\u7528 <code>SUBSTRING()<\/code> \u51fd\u6578\uff0c\u5c0d\u65bc\u9032\u884c\u9ad8\u6548\u7684\u6578\u64da\u8655\u7406\u548c\u5206\u6790\u81f3\u95dc\u91cd\u8981\u3002\u7121\u8ad6\u662f\u6578\u64da\u6e05\u6d17\u3001\u5831\u544a\u751f\u6210\u9084\u662f\u6578\u64da\u9a57\u8b49\uff0c\u638c\u63e1\u9019\u4e9b\u6280\u80fd\u90fd\u5c07\u5927\u5927\u63d0\u5347\u60a8\u7684\u6578\u64da\u64cd\u4f5c\u80fd\u529b\u3002<\/p>\n<p>\u5c0d\u65bc\u5c0b\u6c42\u9ad8\u6548\u7387\u548c\u53ef\u9760\u6027\u7684\u6578\u64da\u8655\u7406\u89e3\u6c7a\u65b9\u6848\u7684\u7528\u6236\u4f86\u8aaa\uff0c<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u63d0\u4f9b\u7684\u670d\u52d9\u662f\u4e00\u500b\u7406\u60f3\u9078\u64c7\u3002\u7121\u8ad6\u662f\u6578\u64da\u5eab\u7ba1\u7406\u3001\u7db2\u7ad9\u6258\u7ba1\u9084\u662f\u61c9\u7528\u7a0b\u5e8f\u958b\u767c\uff0c<a href=\"https:\/\/server.hk\">Server.HK<\/a> \u90fd\u80fd\u63d0\u4f9b\u9802\u7d1a\u7684\u6027\u80fd\u548c\u652f\u6301\u3002<\/p>\n<p>\u63a2\u7d22\u66f4\u591a\u95dc\u65bc <a href=\"https:\/\/server.hk\">\u670d\u52a1\u5668<\/a> \u548c <a href=\"https:\/\/server.hk\">\u4e91\u670d\u52a1\u5668<\/a> \u7684\u4fe1\u606f\uff0c\u6b61\u8fce\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\uff0c\u6211\u5011\u5c07\u70ba\u60a8\u7684\u696d\u52d9\u63d0\u4f9b\u5f37\u5927\u7684\u5f8c\u76fe\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5b78\u7fd2 MSSQL \u6559\u7a0b\u4e2d\u7684 SQL MID() \u51fd\u6578\uff0c\u638c\u63e1\u5982\u4f55\u5f9e\u5b57\u7b26\u4e32\u4e2d\u63d0\u53d6\u5b50\u5b57\u7b26\u4e32\u7684\u6280\u5de7\u8207\u61c9\u7528\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-159987","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/159987","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=159987"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/159987\/revisions"}],"predecessor-version":[{"id":159988,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/159987\/revisions\/159988"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=159987"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=159987"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=159987"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}