{"id":358,"date":"2023-09-16T10:44:52","date_gmt":"2023-09-16T02:44:52","guid":{"rendered":""},"modified":"2023-09-18T11:50:02","modified_gmt":"2023-09-18T03:50:02","slug":"sql%e6%9f%a5%e8%af%a2%e4%b8%ad%e6%88%aa%e5%8f%96%e5%ad%97%e7%ac%a6%e4%b8%b2","status":"publish","type":"post","link":"https:\/\/mushiming.com\/358.html","title":{"rendered":"sql\u67e5\u8be2\u4e2d\u622a\u53d6\u5b57\u7b26\u4e32"},"content":{"rendered":"<h1>SQL \u8bed\u53e5\u4e2d\u67e5\u8be2\u7ed3\u679c\u5b57\u7b26\u622a\u53d6left,right,substrng\u7528\u6cd5<\/h1>\n<h2>&nbsp; &nbsp; \u5728SQL\u7684\u5b9e\u9645\u7528\u9014\u4e2d\uff0c\u7ecf\u5e38\u4f1a\u78b0\u5230\u9700\u8981\u5bf9\u67e5\u8be2\u7ed3\u679c\u503c\u9700\u8981\u505a\u5b57\u6bb5\u7684\u4e00\u4e9b\u622a\u53d6\uff0c\u4e0b\u9762\u5217\u4e3e\u7ecf\u5e38\u7528\u5230\u7684\u4e09\u79cd\u5e38\u7528\u622a\u53d6\u65b9\u5f0f\u3002<\/h2>\n<p>&nbsp; &nbsp; &nbsp; 1.LEFT(str, length)\uff1a\u4ece\u5de6\u8fb9\u5f00\u59cb\u622a\u53d6str\uff0clength\u662f\u622a\u53d6\u7684\u957f\u5ea6\uff1b<\/p>\n<p>&nbsp; &nbsp; &nbsp; 2.RIGHT(str,&nbsp;length)\uff1a\u4ece\u53f3\u8fb9\u5f00\u59cb\u622a\u53d6str\uff0clength\u662f\u622a\u53d6\u7684\u957f\u5ea6\uff1b&nbsp;<\/p>\n<p>&nbsp; &nbsp; &nbsp; 3.SUBSTRING(str&nbsp;&nbsp;,n ,m)\uff1a\u8fd4\u56de\u5b57\u7b26\u4e32str\u4ece\u7b2cn\u4e2a\u5b57\u7b26\u622a\u53d6m\u4e2a\u5b57\u7b26\uff1b<\/p>\n<p>&nbsp;\u4f8b\u5982\uff0c\u6211\u4eec\u6709\u4e00\u4e2a\u5b57\u7b26\u4e32\"Hello, World!\"\uff0c\u6211\u4eec\u60f3\u8981\u63d0\u53d6\u5b50\u5b57\u7b26\u4e32\"World\"\uff0c\u53ef\u4ee5\u4f7f\u7528SUBSTRING\u51fd\u6570\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n<pre><code class=\"language-sql\">SUBSTRING(\"Hello, World!\", 8, 5)\n\n\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c\u5b50\u5b57\u7b26\u4e32\u7684\u8d77\u59cb\u4f4d\u7f6e\u662f8\uff08\u5bf9\u5e94\u4e8e 'W' \u5b57\u7b26\uff09\uff0c\u957f\u5ea6\u4e3a5\u3002\n\nSUBSTRING\u51fd\u6570\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\u7684\u8f93\u51fa\u5c06\u662f\"World\"\u3002\n\n\u8bf7\u6ce8\u610f\uff0c\u5177\u4f53\u7684\u8bed\u6cd5\u548c\u7528\u6cd5\u53ef\u80fd\u4f1a\u6839\u636e\u6570\u636e\u5e93\u7cfb\u7edf\u7684\u4e0d\u540c\u800c\u6709\u6240\u4e0d\u540c\u3002<\/code><\/pre>\n<h3>\u4f8b\u5b50\uff1a\u622a\u53d6\u67e5\u8be2\u7ed3\u679c\u524d10\u4e2a\u5b57\u7b26<\/h3>\n<pre><code>SELECT LEFT(\u5b57\u6bb5\u540d\u79f0,10) from \u8868\u540d\u79f0 WHERE \u6761\u4ef61 and \u6761\u4ef62 ORDER BY alarm_time DESC LIMIT 1;<\/code><\/pre>\n<pre><code>SELECT LEFT(alarm_time,10) from fire_alarm_event WHERE is_deleted = 0 and is_alarm = 1 ORDER BY alarm_time DESC LIMIT 1;\n<\/code><\/pre>\n<h3>&nbsp;\u622a\u53d6\u4e0d\u5b9a\u957f\u5b57\u7b26\u4e32 \uff1a \u67d0\u4e2a\u5b57\u7b26\u4e32\u540e\u9762\u7684\u6240\u6709\u5b57\u7b26\u4e32<\/h3>\n<pre><code class=\"language-sql\">SELECT cage_name,substring(exhibition_img,39,LENGTH(exhibition_img)),substring(cage_img,39,LENGTH(exhibition_img)) from aco_breed_place_species_cage;\n<\/code><\/pre>\n<p>&nbsp;<img decoding=\"async\" src=\"https:\/\/img.mushiming.top\/app\/common_img\/74a6b9db54634eab86fc333adeecdfc2.png\" =\"\" =\"\" alt=\"sql\u67e5\u8be2\u4e2d\u622a\u53d6\u5b57\u7b26\u4e32 (https:\/\/mushiming.com\/) \u6280\u672f\u535a\u5ba2 \u7b2c1\u5f20\" title=\"sql\u67e5\u8be2\u4e2d\u622a\u53d6\u5b57\u7b26\u4e32 \u6280\u672f\u535a\u5ba2 \u7b2c1\u5f20-\u7a46\u4e16\u660e\u535a\u5ba2\" ><\/p>\n<\/p>\n<h3><strong>\u5982\u679c\u5bf9\u60a8\u6709\u5e2e\u52a9\uff0c\u5e2e\u5fd9\u70b9\u8d5e\u5173\u6ce8\u54e6\uff0c\u8c22\u8c22\uff01<\/strong><\/h3>\n","protected":false},"excerpt":{"rendered":"SQL\u8bed\u53e5\u4e2d\u67e5\u8be2\u7ed3\u679c\u5b57\u7b26\u622a\u53d6left,right,substrng\u7528\u6cd5\u5728SQL\u7684\u5b9e\u9645\u7528\u9014\u4e2d\uff0c\u7ecf\u5e38\u4f1a\u78b0\u5230\u9700\u8981\u5bf9\u67e5\u8be2\u7ed3\u679c\u503c\u9700\u8981\u505a\u5b57\u6bb5\u7684\u4e00\u4e9b\u622a\u53d6\uff0c\u4e0b...","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[82],"tags":[],"_links":{"self":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts\/358"}],"collection":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/comments?post=358"}],"version-history":[{"count":0,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts\/358\/revisions"}],"wp:attachment":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/media?parent=358"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/categories?post=358"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/tags?post=358"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}