{"id":5377,"date":"2020-07-29T23:58:08","date_gmt":"2020-07-29T15:58:08","guid":{"rendered":"http:\/\/39.97.231.10\/?p=5377"},"modified":"2020-07-29T23:58:08","modified_gmt":"2020-07-29T15:58:08","slug":"mysql-%e5%87%bd%e6%95%b0%e7%b4%a2%e5%bc%95-functional-indexes","status":"publish","type":"post","link":"http:\/\/www.weijing.co\/?p=5377","title":{"rendered":"MySQL \u51fd\u6570\u7d22\u5f15 (Functional indexes)"},"content":{"rendered":"<div>\n<div>\nMySQL 8.0.13 \u7248\u672c\u5f00\u59cb\u652f\u6301\u51fd\u6570\u7d22\u5f15\uff08Functional indexes\uff09\uff0c\u5728\u6b64\u4e4b\u524d\uff0c\u53ea\u80fd\u4f7f\u7528\u8868\u7684\u5b57\u6bb5\u6216\u8005\u5b57\u6bb5\u524d\u7f00\u6765\u521b\u5efa\u7d22\u5f15\uff0c\u4ece 8.0.13 \u7248\u672c\u5f00\u59cb\uff0c\u53ef\u4ee5\u4f7f\u7528\u51fd\u6570\u6216\u8005\u8868\u8fbe\u5f0f\u7684\u503c\u6765\u521b\u5efa\u7d22\u5f15\uff0c\u8fd9\u4e9b\u51fd\u6570\u6216\u8005\u8868\u8fbe\u5f0f\u7684\u503c\u5e76\u4e0d\u76f4\u63a5\u5b58\u50a8\u5728\u8868\u4e2d\u3002\n<\/div>\n<\/div>\n<div>\n<div>\n<h5>\u51fd\u6570\u7d22\u5f15\u793a\u4f8b\uff1a<\/h5>\n<pre>CREATE TABLE t1 (col1 INT, col2 INT, INDEX func_index ((ABS(col1))));\nCREATE INDEX idx1 ON t1 ((col1 + col2));\nCREATE INDEX idx2 ON t1 ((col1 + col2), (col1 - col2), col1);\nALTER TABLE t1 ADD INDEX ((col1 * 40) DESC);\n<\/pre>\n<p>\u6d89\u53ca\u591a\u4e2a\u5b57\u6bb5\u7684\u7d22\u5f15\uff0c\u53ef\u4ee5\u6df7\u5408\u4f7f\u7528\u51fd\u6570\u7d22\u5f15\u548c\u975e\u51fd\u6570\u7d22\u5f15\uff0c\u5982\u4e0b\uff1a<\/p>\n<pre>alter table sbtest1 add index idx_name_age(name, (age+1));\n<\/pre>\n<p>\u51fd\u6570\u7d22\u5f15\u5b9a\u4e49\u65f6\uff0c\u53ef\u4ee5\u4f7f\u7528 DESC\uff0c ASC \u6307\u5b9a\u5176\u6392\u5e8f\u65b9\u5f0f\uff0c\u5982\u4e0b\uff1a<\/p>\n<pre>alter table sbtest1 add index idx_1(name desc, (age*10) asc );\n<\/pre>\n<h5>\u51fd\u6570\u7d22\u5f15\u7684\u9650\u5236\u6761\u4ef6\uff1a<\/h5>\n<p>\u51fd\u6570\u7d22\u5f15\u5b9e\u9645\u4e0a\u662f\u4f5c\u4e3a\u4e00\u4e2a\u9690\u85cf\u7684\u865a\u62df\u5217\u5b9e\u73b0\u7684\uff0c\u56e0\u6b64\u5176\u5f88\u591a\u9650\u5236\u4e0e\u865a\u62df\u5217\u76f8\u540c\uff0c\u5982\u4e0b\uff1a<\/p>\n<ul>\n<li>\u51fd\u6570\u7d22\u5f15\u7684\u5b57\u6bb5\u6570\u91cf\u53d7\u5230\u8868\u7684\u5b57\u6bb5\u603b\u6570\u9650\u5236<\/li>\n<li>\u51fd\u6570\u7d22\u5f15\u80fd\u591f\u4f7f\u7528\u7684\u51fd\u6570\u4e0e\u865a\u62df\u5217\u4e0a\u80fd\u591f\u4f7f\u7528\u7684\u51fd\u6570\u76f8\u540c<\/li>\n<li>\u5b50\u67e5\u8be2\uff0c\u53c2\u6570\uff0c\u53d8\u91cf\uff0c\u5b58\u50a8\u8fc7\u7a0b\uff0c\u7528\u6237\u5b9a\u4e49\u7684\u51fd\u6570\u4e0d\u5141\u8bb8\u5728\u51fd\u6570\u7d22\u5f15\u4e0a\u4f7f\u7528<\/li>\n<li>\u865a\u62df\u5217\u672c\u8eab\u4e0d\u9700\u8981\u5b58\u50a8\uff0c\u51fd\u6570\u7d22\u5f15\u548c\u5176\u4ed6\u7d22\u5f15\u4e00\u6837\u9700\u8981\u5360\u7528\u5b58\u50a8\u7a7a\u95f4<\/li>\n<li>\u51fd\u6570\u7d22\u5f15\u53ef\u4ee5\u4f7f\u7528 UNIQUE\u00a0 \u6807\u8bc6\uff0c\u4f46\u662f\u4e3b\u952e\u4e0d\u80fd\u4f7f\u7528\u51fd\u6570\u7d22\u5f15\uff0c\u4e3b\u952e\u8981\u6c42\u88ab\u5b58\u50a8\uff0c\u4f46\u662f\u51fd\u6570\u7d22\u5f15\u7531\u4e8e\u5176\u4f7f\u7528\u7684\u865a\u62df\u5217\u4e0d\u80fd\u88ab\u5b58\u50a8\uff0c\u56e0\u6b64\u4e3b\u952e\u4e0d\u80fd\u4f7f\u7528\u51fd\u6570\u7d22\u5f15<\/li>\n<li>\u5982\u679c\u8868\u4e2d\u6ca1\u6709\u4e3b\u952e\uff0c\u90a3\u4e48 InnoDB \u5c06\u4f1a\u4f7f\u5176\u975e\u7a7a\u7684\u552f\u4e00\u7d22\u5f15\u4f5c\u4e3a\u4e3b\u952e\uff0c\u56e0\u6b64\u8be5\u552f\u4e00\u7d22\u5f15\u4e0d\u80fd\u5b9a\u4e49\u4e3a\u51fd\u6570\u7d22\u5f15<\/li>\n<li>\u51fd\u6570\u7d22\u5f15\u4e0d\u5141\u8bb8\u5728\u5916\u952e\u4e2d\u4f7f\u7528<\/li>\n<li>\u7a7a\u95f4\u7d22\u5f15\u548c\u5168\u6587\u7d22\u5f15\u4e0d\u80fd\u5b9a\u4e49\u4e3a\u51fd\u6570\u7d22\u5f15<\/li>\n<li>\u5bf9\u4e8e\u975e\u51fd\u6570\u7684\u7d22\u5f15\uff0c\u5982\u679c\u521b\u5efa\u76f8\u540c\u7684\u7d22\u5f15\uff0c\u5c06\u4f1a\u6709\u4e00\u4e2a\u544a\u8b66\u4fe1\u606f\uff0c\u800c\u51fd\u6570\u7d22\u5f15\u5219\u4e0d\u4f1a<\/li>\n<li>\u5982\u679c\u4e00\u4e2a\u5b57\u6bb5\u88ab\u7528\u4e8e\u51fd\u6570\u7d22\u5f15\uff0c\u90a3\u4e48\u5220\u9664\u8be5\u5b57\u6bb5\u524d\uff0c\u9700\u8981\u5148\u5220\u9664\u8be5\u51fd\u6570\u7d22\u5f15\uff0c\u5426\u5219\u5220\u9664\u8be5\u5b57\u6bb5\u4f1a\u62a5\u9519<\/li>\n<li>\u975e\u51fd\u6570\u7d22\u5f15\u652f\u6301\u5bf9\u5b57\u6bb5\u524d\u7f00\u8fdb\u884c\u7d22\u5f15\uff0c\u51fd\u6570\u7d22\u5f15\u4e0d\u652f\u6301\u524d\u7f00\u3002\u53ef\u4ee5\u4f7f\u7528 SUBSTRING() \u6216\u8005 CAST() \u3002\u4f46\u662f\u67e5\u8be2 SQL \u4e2d\u7684\u53c2\u6570\u5fc5\u987b\u4e0e\u51fd\u6570\u7d22\u5f15\u5b9a\u4e49\u65f6\u7684\u53c2\u6570\u5b8c\u5168\u76f8\u540c\u624d\u80fd\u4f7f\u7528\u8be5\u7d22\u5f15\uff0c\u5982\u4e0b\u793a\u4f8b\uff1a<\/li>\n<\/ul>\n<pre>CREATE TABLE tbl (\n  col1 LONGTEXT,\n  INDEX idx1 ((SUBSTRING(col1, 1, 10)))\n);\nSELECT * FROM tbl WHERE SUBSTRING(col1, 1, 9) = \\'123456789\\';\nSELECT * FROM tbl WHERE SUBSTRING(col1, 1, 10) = \\'1234567890\\';\n<\/pre>\n<p>SUBSTRING(col1, 1, 9) \u65e0\u6cd5\u4f7f\u7528\u51fd\u6570\u7d22\u5f15\uff0cSUBSTRING(col1, 1, 10) \u53ef\u4ee5\u4f7f\u7528\u51fd\u6570\u7d22\u5f15\u3002\n<\/p><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>MySQL 8.0.13 \u7248\u672c\u5f00\u59cb\u652f\u6301\u51fd\u6570\u7d22\u5f15\uff08Functional indexes\uff09\uff0c\u5728\u6b64\u4e4b\u524d\uff0c\u53ea\u80fd\u4f7f\u7528\u8868\u7684 &hellip;<\/p>\n<p class=\"read-more\"> <a class=\"\" href=\"http:\/\/www.weijing.co\/?p=5377\"> <span class=\"screen-reader-text\">MySQL \u51fd\u6570\u7d22\u5f15 (Functional indexes)<\/span> \u67e5\u770b\u5168\u6587 &raquo;<\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":""},"categories":[90,88],"tags":[],"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false,"mailpoet_newsletter_max":false,"woocommerce_thumbnail":false,"woocommerce_single":false,"woocommerce_gallery_thumbnail":false,"shop_catalog":false,"shop_single":false,"shop_thumbnail":false},"uagb_author_info":{"display_name":"weijing","author_link":"http:\/\/www.weijing.co\/?author=4"},"uagb_comment_info":0,"uagb_excerpt":"MySQL 8.0.13 \u7248\u672c\u5f00\u59cb\u652f\u6301\u51fd\u6570\u7d22\u5f15\uff08Functional indexes\uff09\uff0c\u5728\u6b64\u4e4b\u524d\uff0c\u53ea\u80fd\u4f7f\u7528\u8868\u7684&hellip;","_links":{"self":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/posts\/5377"}],"collection":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5377"}],"version-history":[{"count":0,"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/posts\/5377\/revisions"}],"wp:attachment":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5377"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5377"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5377"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}