{"id":60431,"date":"2024-10-13T02:48:15","date_gmt":"2024-10-12T18:48:15","guid":{"rendered":"https:\/\/server.hk\/cnblog\/60431\/"},"modified":"2024-10-13T02:48:15","modified_gmt":"2024-10-12T18:48:15","slug":"db2%e5%b8%b8%e7%94%a8%e5%87%bd%e6%95%b8%e8%a9%b3%e8%a7%a3%e4%b9%8b%e9%a1%9e%e5%9e%8b%e8%bd%89%e6%8f%9b%e5%87%bd%e6%95%b8%e5%a4%a7%e7%9b%a4%e9%bb%9e","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/60431\/","title":{"rendered":"DB2\u5e38\u7528\u51fd\u6578\u8a73\u89e3\u4e4b\u985e\u578b\u8f49\u63db\u51fd\u6578\u5927\u76e4\u9ede"},"content":{"rendered":"<h1 id=\"db2%e5%b8%b8%e7%94%a8%e5%87%bd%e6%95%b8%e8%a9%b3%e8%a7%a3%e4%b9%8b%e9%a1%9e%e5%9e%8b%e8%bd%89%e6%8f%9b%e5%87%bd%e6%95%b8%e5%a4%a7%e7%9b%a4%e9%bb%9e-kGzIIKYfob\">DB2\u5e38\u7528\u51fd\u6578\u8a73\u89e3\u4e4b\u985e\u578b\u8f49\u63db\u51fd\u6578\u5927\u76e4\u9ede<\/h1>\n<p>\u5728\u8cc7\u6599\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0c\u985e\u578b\u8f49\u63db\u51fd\u6578\u662f\u975e\u5e38\u91cd\u8981\u7684\u5de5\u5177\uff0c\u7279\u5225\u662f\u5728\u8655\u7406\u4e0d\u540c\u6578\u64da\u985e\u578b\u4e4b\u9593\u7684\u8f49\u63db\u6642\u3002IBM\u7684DB2\u8cc7\u6599\u5eab\u7cfb\u7d71\u63d0\u4f9b\u4e86\u591a\u7a2e\u985e\u578b\u8f49\u63db\u51fd\u6578\uff0c\u9019\u4e9b\u51fd\u6578\u80fd\u5920\u5e6b\u52a9\u958b\u767c\u8005\u548c\u8cc7\u6599\u5eab\u7ba1\u7406\u54e1\u6709\u6548\u5730\u8655\u7406\u6578\u64da\u3002\u672c\u6587\u5c07\u8a73\u7d30\u4ecb\u7d39DB2\u4e2d\u7684\u5e38\u7528\u985e\u578b\u8f49\u63db\u51fd\u6578\u53ca\u5176\u4f7f\u7528\u65b9\u6cd5\u3002<\/p>\n<h2 id=\"1-%e9%a1%9e%e5%9e%8b%e8%bd%89%e6%8f%9b%e5%87%bd%e6%95%b8%e6%a6%82%e8%bf%b0-kGzIIKYfob\">1. \u985e\u578b\u8f49\u63db\u51fd\u6578\u6982\u8ff0<\/h2>\n<p>\u985e\u578b\u8f49\u63db\u51fd\u6578\u7684\u4e3b\u8981\u529f\u80fd\u662f\u5c07\u4e00\u7a2e\u6578\u64da\u985e\u578b\u8f49\u63db\u70ba\u53e6\u4e00\u7a2e\u6578\u64da\u985e\u578b\u3002\u9019\u5728\u9032\u884c\u6578\u64da\u6bd4\u8f03\u3001\u8a08\u7b97\u6216\u5b58\u5132\u6642\u5c24\u70ba\u91cd\u8981\u3002DB2\u63d0\u4f9b\u4e86\u5e7e\u7a2e\u5e38\u7528\u7684\u985e\u578b\u8f49\u63db\u51fd\u6578\uff0c\u5305\u62ec\uff1a<\/p>\n<ul>\n<li><code>CAST<\/code><\/li>\n<li><code>CONVERT<\/code><\/li>\n<li><code>VARCHAR<\/code><\/li>\n<li><code>DECIMAL<\/code><\/li>\n<\/ul>\n<h2 id=\"2-cast-%e5%87%bd%e6%95%b8-kGzIIKYfob\">2. CAST \u51fd\u6578<\/h2>\n<p><code>CAST<\/code> \u51fd\u6578\u662fDB2\u4e2d\u6700\u5e38\u7528\u7684\u985e\u578b\u8f49\u63db\u51fd\u6578\u4e4b\u4e00\u3002\u5b83\u7684\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>CAST(expression AS target_data_type)<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u5c07\u4e00\u500b\u6574\u6578\u8f49\u63db\u70ba\u5b57\u4e32\uff1a<\/p>\n<pre><code>SELECT CAST(123 AS VARCHAR(10)) AS ConvertedValue FROM SYSIBM.SYSDUMMY1;<\/code><\/pre>\n<p>\u9019\u5c07\u8fd4\u56de\u4e00\u500b\u5b57\u4e32\u201c123\u201d\u3002<\/p>\n<h2 id=\"3-convert-%e5%87%bd%e6%95%b8-kGzIIKYfob\">3. CONVERT \u51fd\u6578<\/h2>\n<p><code>CONVERT<\/code> \u51fd\u6578\u7684\u529f\u80fd\u8207 <code>CAST<\/code> \u51fd\u6578\u76f8\u4f3c\uff0c\u4f46\u5176\u8a9e\u6cd5\u7565\u6709\u4e0d\u540c\uff1a<\/p>\n<pre><code>CONVERT(target_data_type, expression)<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u5c07\u4e00\u500b\u5b57\u4e32\u8f49\u63db\u70ba\u6574\u6578\uff1a<\/p>\n<pre><code>SELECT CONVERT(INTEGER, '456') AS ConvertedValue FROM SYSIBM.SYSDUMMY1;<\/code><\/pre>\n<p>\u9019\u5c07\u8fd4\u56de\u6574\u6578456\u3002<\/p>\n<h2 id=\"4-varchar-%e5%87%bd%e6%95%b8-kGzIIKYfob\">4. VARCHAR \u51fd\u6578<\/h2>\n<p><code>VARCHAR<\/code> \u51fd\u6578\u7528\u65bc\u5c07\u5176\u4ed6\u6578\u64da\u985e\u578b\u8f49\u63db\u70ba\u53ef\u8b8a\u9577\u5ea6\u7684\u5b57\u4e32\u3002\u5176\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>VARCHAR(expression, length)<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u5c07\u4e00\u500b\u6574\u6578\u8f49\u63db\u70ba\u5b57\u4e32\uff0c\u4e26\u6307\u5b9a\u5b57\u4e32\u7684\u6700\u5927\u9577\u5ea6\uff1a<\/p>\n<pre><code>SELECT VARCHAR(789, 5) AS ConvertedValue FROM SYSIBM.SYSDUMMY1;<\/code><\/pre>\n<p>\u9019\u5c07\u8fd4\u56de\u5b57\u4e32\u201c789\u201d\u3002<\/p>\n<h2 id=\"5-decimal-%e5%87%bd%e6%95%b8-kGzIIKYfob\">5. DECIMAL \u51fd\u6578<\/h2>\n<p><code>DECIMAL<\/code> \u51fd\u6578\u7528\u65bc\u5c07\u6578\u64da\u8f49\u63db\u70ba\u5341\u9032\u5236\u683c\u5f0f\u3002\u5176\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>DECIMAL(expression, precision, scale)<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u5c07\u4e00\u500b\u6d6e\u9ede\u6578\u8f49\u63db\u70ba\u5341\u9032\u5236\uff1a<\/p>\n<pre><code>SELECT DECIMAL(123.456, 5, 2) AS ConvertedValue FROM SYSIBM.SYSDUMMY1;<\/code><\/pre>\n<p>\u9019\u5c07\u8fd4\u56de\u5341\u9032\u5236\u6578\u5b57\u201c123.46\u201d\u3002<\/p>\n<h2 id=\"6-%e4%bd%bf%e7%94%a8%e5%a0%b4%e6%99%af-kGzIIKYfob\">6. \u4f7f\u7528\u5834\u666f<\/h2>\n<p>\u985e\u578b\u8f49\u63db\u51fd\u6578\u5728\u591a\u7a2e\u5834\u666f\u4e2d\u90fd\u975e\u5e38\u6709\u7528\uff0c\u4f8b\u5982\uff1a<\/p>\n<ul>\n<li>\u5728\u9032\u884c\u6578\u64da\u6bd4\u8f03\u6642\uff0c\u78ba\u4fdd\u6578\u64da\u985e\u578b\u4e00\u81f4\u3002<\/li>\n<li>\u5728\u5831\u544a\u751f\u6210\u4e2d\uff0c\u5c07\u6578\u64da\u683c\u5f0f\u5316\u70ba\u53ef\u8b80\u6027\u66f4\u9ad8\u7684\u5f62\u5f0f\u3002<\/li>\n<li>\u5728\u6578\u64da\u6e05\u7406\u904e\u7a0b\u4e2d\uff0c\u5c07\u4e0d\u4e00\u81f4\u7684\u6578\u64da\u985e\u578b\u7d71\u4e00\u3002<\/li>\n<\/ul>\n<h2 id=\"7-%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-kGzIIKYfob\">7. \u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u5728\u4f7f\u7528\u985e\u578b\u8f49\u63db\u51fd\u6578\u6642\uff0c\u958b\u767c\u8005\u61c9\u6ce8\u610f\u4ee5\u4e0b\u5e7e\u9ede\uff1a<\/p>\n<ul>\n<li>\u78ba\u4fdd\u8f49\u63db\u7684\u6578\u64da\u985e\u578b\u4e4b\u9593\u662f\u517c\u5bb9\u7684\uff0c\u5426\u5247\u53ef\u80fd\u6703\u5c0e\u81f4\u932f\u8aa4\u3002<\/li>\n<li>\u5728\u9032\u884c\u6578\u64da\u8f49\u63db\u6642\uff0c\u6ce8\u610f\u7cbe\u5ea6\u548c\u7bc4\u570d\u7684\u554f\u984c\uff0c\u7279\u5225\u662f\u5728\u8655\u7406\u6d6e\u9ede\u6578\u548c\u6574\u6578\u6642\u3002<\/li>\n<li>\u4f7f\u7528 <code>NULL<\/code> \u503c\u6642\uff0c\u8f49\u63db\u7d50\u679c\u4e5f\u6703\u662f <code>NULL<\/code>\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-kGzIIKYfob\">\u7e3d\u7d50<\/h2>\n<p>DB2\u7684\u985e\u578b\u8f49\u63db\u51fd\u6578\u70ba\u958b\u767c\u8005\u63d0\u4f9b\u4e86\u9748\u6d3b\u7684\u6578\u64da\u8655\u7406\u80fd\u529b\uff0c\u80fd\u5920\u6709\u6548\u5730\u89e3\u6c7a\u4e0d\u540c\u6578\u64da\u985e\u578b\u4e4b\u9593\u7684\u8f49\u63db\u554f\u984c\u3002\u7121\u8ad6\u662f\u5728\u6578\u64da\u6bd4\u8f03\u3001\u5831\u544a\u751f\u6210\u9084\u662f\u6578\u64da\u6e05\u7406\u4e2d\uff0c\u9019\u4e9b\u51fd\u6578\u90fd\u80fd\u767c\u63ee\u91cd\u8981\u4f5c\u7528\u3002\u4e86\u89e3\u548c\u638c\u63e1\u9019\u4e9b\u51fd\u6578\u7684\u4f7f\u7528\u65b9\u6cd5\uff0c\u5c07\u6709\u52a9\u65bc\u63d0\u9ad8\u8cc7\u6599\u5eab\u64cd\u4f5c\u7684\u6548\u7387\u548c\u6e96\u78ba\u6027\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bc <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u670d\u52d9\u6709\u8208\u8da3\uff0c\u6b61\u8fce\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4ee5\u7372\u53d6\u66f4\u591a\u8cc7\u8a0a\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22DB2\u5e38\u7528\u51fd\u6578\uff0c\u6df1\u5165\u89e3\u6790\u5404\u985e\u578b\u8f49\u63db\u51fd\u6578\uff0c\u52a9\u60a8\u9ad8\u6548\u8655\u7406\u6578\u64da\u8f49\u63db\u8207\u7ba1\u7406\u3002<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-60431","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60431","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"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=60431"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60431\/revisions"}],"predecessor-version":[{"id":60432,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60431\/revisions\/60432"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=60431"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=60431"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=60431"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}