{"id":1238,"date":"2020-05-18T10:06:56","date_gmt":"2020-05-18T02:06:56","guid":{"rendered":"http:\/\/39.97.231.10\/?p=1238"},"modified":"2020-05-18T10:06:56","modified_gmt":"2020-05-18T02:06:56","slug":"mysql%e7%9a%84%e8%a1%8c%e8%bd%ac%e5%88%97-%e5%88%97%e8%bd%ac%e8%a1%8c-%e8%bf%9e%e6%8e%a5%e5%ad%97%e7%ac%a6%e4%b8%b2-concat-concat_ws-group_concat%e5%87%bd%e6%95%b0%e7%94%a8%e6%b3%95","status":"publish","type":"post","link":"http:\/\/www.weijing.co\/?p=1238","title":{"rendered":"MySQL\u7684\u884c\u8f6c\u5217 \u5217\u8f6c\u884c \u8fde\u63a5\u5b57\u7b26\u4e32 concat concat_ws group_concat\u51fd\u6570\u7528\u6cd5"},"content":{"rendered":"<ul>\n<li><strong>\u521b\u5efaMySQL\u6570\u636e\u5e93\u8868\u7ed3\u6784<\/strong><\/li>\n<\/ul>\n<pre>DROP TABLE IF EXISTS `weijing`;\nCREATE TABLE `weijing` (\n`Id` int(11) NOT NULL AUTO_INCREMENT,\n`Name` varchar(20) DEFAULT NULL,\n`Date` date DEFAULT NULL,\n`Scount` int(11) DEFAULT NULL,\nPRIMARY KEY (`Id`)\n) ENGINE=InnoDB AUTO_INCREMENT=9 DEFAULT CHARSET=utf8;<\/pre>\n<ul>\n<li><strong>\u63d2\u5165\u8868\u8bb0\u5f55<\/strong><\/li>\n<\/ul>\n<pre>INSERT INTO `weijing` VALUES (\\'1\\', \\'\u6f4d\u9cb8\\', \\'2020-05-01\\', \\'10000\\');\nINSERT INTO `weijing` VALUES (\\'2\\', \\'\u6587\u7ae0\\', \\'2020-05-01\\', \\'20000\\');\nINSERT INTO `weijing` VALUES (\\'3\\', \\'\u6f4d\u9cb8\\', \\'2020-05-02\\', \\'30000\\');\nINSERT INTO `weijing` VALUES (\\'4\\', \\'\u6587\u7ae0\\', \\'2020-05-02\\', \\'35000\\');\nINSERT INTO `weijing` VALUES (\\'5\\', \\'\u6f4d\u9cb8\\', \\'2020-05-03\\', \\'31000\\');\nINSERT INTO `weijing` VALUES (\\'6\\', \\'\u6587\u7ae0\\', \\'2020-05-03\\', \\'36000\\');\nINSERT INTO `weijing` VALUES (\\'7\\', \\'\u6f4d\u9cb8\\', \\'2020-05-04\\', \\'35000\\');\nINSERT INTO `weijing` VALUES (\\'8\\', \\'\u6587\u7ae0\\', \\'2020-05-04\\', \\'38000\\');<\/pre>\n<ul>\n<li><strong>\u67e5\u770b\u63d2\u5165\u7684\u8868\u6570\u636e<\/strong><\/li>\n<\/ul>\n<pre>mysql&gt; select * from weijing;\n+----+--------+------------+--------+\n| Id | Name   | Date       | Scount |\n+----+--------+------------+--------+\n|  1 | \u6f4d\u9cb8   | 2020-05-01 |  10000 |\n|  2 | \u6587\u7ae0   | 2020-05-01 |  20000 |\n|  3 | \u6f4d\u9cb8   | 2020-05-02 |  30000 |\n|  4 | \u6587\u7ae0   | 2020-05-02 |  35000 |\n|  5 | \u6f4d\u9cb8   | 2020-05-03 |  31000 |\n|  6 | \u6587\u7ae0   | 2020-05-03 |  36000 |\n|  7 | \u6f4d\u9cb8   | 2020-05-04 |  35000 |\n|  8 | \u6587\u7ae0   | 2020-05-04 |  38000 |\n+----+--------+------------+--------+\n8 rows in set (0.00 sec)<\/pre>\n<ul>\n<li><strong>\u5217\u8f6c\u884c\u7edf\u8ba1\u6570\u636e<\/strong><\/li>\n<\/ul>\n<pre>mysql&gt; SELECT Date , MAX(CASE NAME WHEN \\'\u6587\u7ae0\\' THEN Scount ELSE 0 END ) \u6587\u7ae0,  MAX(CASE NAME WHEN \\'\u6f4d\u9cb8\\' THEN Scount ELSE 0 END ) \u6f4d\u9cb8   FROM weijing  GROUP BY Date;\n+------------+--------+--------+\n| Date       | \u6587\u7ae0   | \u6f4d\u9cb8   |\n+------------+--------+--------+\n| 2020-05-01 |  20000 |  10000 |\n| 2020-05-02 |  35000 |  30000 |\n| 2020-05-03 |  36000 |  31000 |\n| 2020-05-04 |  38000 |  35000 |\n+------------+--------+--------+\n4 rows in set (0.00 sec)<\/pre>\n<ul>\n<li><strong>\u884c\u8f6c\u5217\u7edf\u8ba1\u6570\u636e<\/strong><\/li>\n<\/ul>\n<pre>mysql&gt; select date,group_concat(name,\\'\u7edf\u8ba1:\\',scount) as \\'\u5217\u8f6c\u884c\\' from weijing group by date;\n+------------+---------------------------------------+\n| date       | \u5217\u8f6c\u884c                                |\n+------------+---------------------------------------+\n| 2020-05-01 | \u6f4d\u9cb8\u7edf\u8ba1:10000,\u6587\u7ae0\u7edf\u8ba1:20000         |\n| 2020-05-02 | \u6f4d\u9cb8\u7edf\u8ba1:30000,\u6587\u7ae0\u7edf\u8ba1:35000         |\n| 2020-05-03 | \u6f4d\u9cb8\u7edf\u8ba1:31000,\u6587\u7ae0\u7edf\u8ba1:36000         |\n| 2020-05-04 | \u6f4d\u9cb8\u7edf\u8ba1:35000,\u6587\u7ae0\u7edf\u8ba1:38000         |\n+------------+---------------------------------------+\n4 rows in set (0.00 sec)\nmysql&gt; select date,group_concat(name,\\'\u7edf\u8ba1:\\',scount) as \\'\u5217\u8f6c\u884c\\' from weijing group by date,name;\n+------------+--------------------+\n| date       | \u5217\u8f6c\u884c             |\n+------------+--------------------+\n| 2020-05-01 | \u6587\u7ae0\u7edf\u8ba1:20000     |\n| 2020-05-01 | \u6f4d\u9cb8\u7edf\u8ba1:10000     |\n| 2020-05-02 | \u6587\u7ae0\u7edf\u8ba1:35000     |\n| 2020-05-02 | \u6f4d\u9cb8\u7edf\u8ba1:30000     |\n| 2020-05-03 | \u6587\u7ae0\u7edf\u8ba1:36000     |\n| 2020-05-03 | \u6f4d\u9cb8\u7edf\u8ba1:31000     |\n| 2020-05-04 | \u6587\u7ae0\u7edf\u8ba1:38000     |\n| 2020-05-04 | \u6f4d\u9cb8\u7edf\u8ba1:35000     |\n+------------+--------------------+\n8 rows in set (0.00 sec)<\/pre>\n<div><\/div>\n<ul>\n<li>MySQL\u7684\u884c\u8f6c\u5217\u3001\u5217\u8f6c\u884c\u3001\u8fde\u63a5\u5b57\u7b26\u4e32 \u00a0concat\u3001concat_ws\u3001group_concat\u51fd\u6570\u7528\u6cd5<\/li>\n<\/ul>\n<div style=\\\"padding-left: 40px;\\\">\u4f7f\u7528\u65b9\u6cd5\uff1a<\/div>\n<div style=\\\"padding-left: 40px;\\\">CONCAT(str1,str2,\u2026)<\/div>\n<div style=\\\"padding-left: 40px;\\\">\u8fd4\u56de\u7ed3\u679c\u4e3a\u8fde\u63a5\u53c2\u6570\u4ea7\u751f\u7684\u5b57\u7b26\u4e32\u3002\u5982\u6709\u4efb\u4f55\u4e00\u4e2a\u53c2\u6570\u4e3aNULL\u00a0\uff0c\u5219\u8fd4\u56de\u503c\u4e3a\u00a0NULL\u3002<\/div>\n<div style=\\\"padding-left: 40px;\\\">\u6ce8\u610f\uff1a<\/div>\n<div style=\\\"padding-left: 40px;\\\">\u5982\u679c\u6240\u6709\u53c2\u6570\u5747\u4e3a\u975e\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32\uff0c\u5219\u7ed3\u679c\u4e3a\u975e\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32\u3002<\/div>\n<div style=\\\"padding-left: 40px;\\\">\u5982\u679c\u81ea\u53d8\u91cf\u4e2d\u542b\u6709\u4efb\u4e00\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32\uff0c\u5219\u7ed3\u679c\u4e3a\u4e00\u4e2a\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32\u3002<\/div>\n<div style=\\\"padding-left: 40px;\\\">\u4e00\u4e2a\u6570\u5b57\u53c2\u6570\u88ab\u8f6c\u5316\u4e3a\u4e0e\u4e4b\u76f8\u7b49\u7684\u4e8c\u8fdb\u5236\u5b57\u7b26\u4e32\u683c\u5f0f\uff1b\u82e5\u8981\u907f\u514d\u8fd9\u79cd\u60c5\u51b5\uff0c\u53ef\u4f7f\u7528\u663e\u5f0f\u7c7b\u578b\u00a0cast,\u00a0\u4f8b\u5982\uff1a<\/div>\n<div style=\\\"padding-left: 40px;\\\">SELECT\u00a0CONCAT(CAST(int_col\u00a0AS\u00a0CHAR),\u00a0char_col)<\/div>\n<div><\/div>\n<div style=\\\"padding-left: 40px;\\\"><strong>MySQL\u7684concat\u51fd\u6570\u53ef\u4ee5\u8fde\u63a5\u4e00\u4e2a\u6216\u8005\u591a\u4e2a\u5b57\u7b26\u4e32\uff1a<\/strong><\/div>\n<div>\n<pre style=\\\"padding-left: 40px;\\\">mysql&gt; select concat(1);\n+-----------+\n| concat(1) |\n+-----------+\n| 1 |\n+-----------+\n1 row in set (0.00 sec)\nmysql&gt; select concat(1,2,3);\n+---------------+\n| concat(1,2,3) |\n+---------------+\n| 123 |\n+---------------+\n1 row in set (0.00 sec)<\/pre>\n<\/div>\n<div style=\\\"padding-left: 40px;\\\"><strong>MySQL\u7684concat\u51fd\u6570\u5728\u8fde\u63a5\u5b57\u7b26\u4e32\u7684\u65f6\u5019\uff0c\u53ea\u8981\u5176\u4e2d\u4e00\u4e2a\u662fNULL,\u90a3\u4e48\u5c06\u8fd4\u56deNULL<\/strong><\/div>\n<pre style=\\\"padding-left: 40px;\\\">mysql&gt; select concat(1,2,3,null);\n+--------------------+\n| concat(1,2,3,null) |\n+--------------------+\n| NULL |\n+--------------------+\n1 row in set (0.00 sec)<\/pre>\n<div><\/div>\n<div style=\\\"padding-left: 40px;\\\"><strong>MySQL\u4e2dconcat_ws\u51fd\u6570<\/strong><\/div>\n<div style=\\\"padding-left: 40px;\\\">\u4f7f\u7528\u65b9\u6cd5\uff1a<\/div>\n<div style=\\\"padding-left: 40px;\\\">CONCAT_WS(separator,str1,str2,&#8230;)<\/div>\n<div style=\\\"padding-left: 40px;\\\">CONCAT_WS()\u00a0\u4ee3\u8868\u00a0CONCAT\u00a0With\u00a0Separator\u00a0\uff0c\u662fCONCAT()\u7684\u7279\u6b8a\u5f62\u5f0f\u3002\u7b2c\u4e00\u4e2a\u53c2\u6570\u662f\u5176\u5b83\u53c2\u6570\u7684\u5206\u9694\u7b26\u3002\u5206\u9694\u7b26\u7684\u4f4d\u7f6e\u653e\u5728\u8981\u8fde\u63a5\u7684\u4e24\u4e2a\u5b57\u7b26\u4e32\u4e4b\u95f4\u3002\u5206\u9694\u7b26\u53ef\u4ee5\u662f\u4e00\u4e2a\u5b57\u7b26\u4e32\uff0c\u4e5f\u53ef\u4ee5\u662f\u5176\u5b83\u53c2\u6570\u3002<\/div>\n<div style=\\\"padding-left: 40px;\\\">\u6ce8\u610f\uff1a<\/div>\n<div style=\\\"padding-left: 40px;\\\">\u5982\u679c\u5206\u9694\u7b26\u4e3a\u00a0NULL\uff0c\u5219\u7ed3\u679c\u4e3a\u00a0NULL\u3002\u51fd\u6570\u4f1a\u5ffd\u7565\u4efb\u4f55\u5206\u9694\u7b26\u53c2\u6570\u540e\u7684\u00a0NULL\u00a0\u503c\u3002<\/div>\n<div style=\\\"padding-left: 40px;\\\">concat_ws\u51fd\u6570\u5728\u6267\u884c\u7684\u65f6\u5019,\u4e0d\u4f1a\u56e0\u4e3aNULL\u503c\u800c\u8fd4\u56deNULL<\/div>\n<div>\n<pre style=\\\"padding-left: 40px;\\\">mysql&gt; select concat_ws(\\',\\',1,2,3,null);\n+---------------------------+\n| concat_ws(\\',\\',1,2,3,null) |\n+---------------------------+\n| 1,2,3 |\n+---------------------------+\n1 row in set (0.00 sec)\nmysql&gt; select concat_ws(null,1,2,3);\n+-----------------------+\n| concat_ws(null,1,2,3) |\n+-----------------------+\n| NULL |\n+-----------------------+\n1 row in set (0.00 sec)<\/pre>\n<\/div>\n<div><\/div>\n<div style=\\\"padding-left: 40px;\\\"><strong>MySQL\u4e2dgroup_concat\u51fd\u6570<\/strong><\/div>\n<div style=\\\"padding-left: 40px;\\\">\u5b8c\u6574\u7684\u8bed\u6cd5\u5982\u4e0b\uff1a<\/div>\n<div style=\\\"padding-left: 40px;\\\">group_concat([DISTINCT]\u00a0\u8981\u8fde\u63a5\u7684\u5b57\u6bb5\u00a0[Order\u00a0BY\u00a0ASC\/DESC\u00a0\u6392\u5e8f\u5b57\u6bb5]\u00a0[Separator\u00a0\\&#8217;\u5206\u9694\u7b26\\&#8217;])<\/div>\n<div><\/div>\n<div style=\\\"padding-left: 40px;\\\">\u4ee5name\u5206\u7ec4\uff0c\u628adate\u5b57\u6bb5\u7684\u503c\u6253\u5370\u5728\u4e00\u884c\uff0c\u9017\u53f7\u5206\u9694(\u9ed8\u8ba4)<\/div>\n<pre>mysql&gt; select name,group_concat(date) from weijing group by name;\n+--------+-----------------------------------------------------------------------------------------+\n| name   | group_concat(date)                                                                      |\n+--------+-----------------------------------------------------------------------------------------+\n| \u6587\u7ae0   | 2020-05-04,2020-05-02,2020-05-04,2020-05-03,2020-05-03,2020-05-02,2020-05-01,2020-05-01 |\n| \u6f4d\u9cb8   | 2020-05-03,2020-05-04,2020-05-02,2020-05-01,2020-05-04,2020-05-03,2020-05-02,2020-05-01 |\n+--------+-----------------------------------------------------------------------------------------+\n2 rows in set (0.00 sec)<\/pre>\n<div style=\\\"padding-left: 40px;\\\">\u4ee5name\u5206\u7ec4\uff0c\u628adate\u5b57\u6bb5\u7684\u503c\u6253\u5370\u5728\u4e00\u884c\uff0c\u5206\u53f7\u5206\u9694\u3002<\/div>\n<pre style=\\\"padding-left: 40px;\\\">mysql&gt; select name,group_concat(date separator \\';\\') from weijing group by name;\n+--------+-----------------------------------------------------------------------------------------+\n| name   | group_concat(date separator \\';\\')                                                        |\n+--------+-----------------------------------------------------------------------------------------+\n| \u6587\u7ae0   | 2020-05-04;2020-05-02;2020-05-04;2020-05-03;2020-05-03;2020-05-02;2020-05-01;2020-05-01 |\n| \u6f4d\u9cb8   | 2020-05-03;2020-05-04;2020-05-02;2020-05-01;2020-05-04;2020-05-03;2020-05-02;2020-05-01 |\n+--------+-----------------------------------------------------------------------------------------+\n2 rows in set (0.00 sec)<\/pre>\n<div><\/div>\n<div>\u4ee5name\u5206\u7ec4\uff0c\u628a\u53bb\u5197\u4f59\u7684date\u5b57\u6bb5\u7684\u503c\u6253\u5370\u5728\u4e00\u884c\uff0c\u9017\u53f7\u5206\u9694\u3002<\/div>\n<pre>mysql&gt; select name,group_concat(distinct date) from weijing group by name;\n+--------+---------------------------------------------+\n| name   | group_concat(distinct date)                 |\n+--------+---------------------------------------------+\n| \u6587\u7ae0    | 2020-05-04,2020-05-02,2020-05-03,2020-05-01 |\n| \u6f4d\u9cb8    | 2020-05-03,2020-05-04,2020-05-02,2020-05-01 |\n+--------+---------------------------------------------+\n2 rows in set (0.01 sec)<\/pre>\n<div><\/div>\n<div style=\\\"padding-left: 40px;\\\">\u4ee5name\u5206\u7ec4\uff0c\u628adate\u5b57\u6bb5\u7684\u503c\u6253\u5370\u5728\u4e00\u884c\uff0c\u9017\u53f7\u5206\u9694\uff0c\u4ee5date\u6392\u5012\u5e8f.<\/div>\n<pre style=\\\"padding-left: 40px;\\\">mysql&gt; select name,group_concat(date order by date desc) from weijing group by name;\n+--------+-----------------------------------------------------------------------------------------+\n| name | group_concat(date order by date desc) |\n+--------+-----------------------------------------------------------------------------------------+\n| \u6587\u7ae0 | 2020-05-04,2020-05-04,2020-05-03,2020-05-03,2020-05-02,2020-05-02,2020-05-01,2020-05-01 |\n| \u6f4d\u9cb8 | 2020-05-04,2020-05-04,2020-05-03,2020-05-03,2020-05-02,2020-05-02,2020-05-01,2020-05-01 |\n+--------+-----------------------------------------------------------------------------------------+\n2 rows in set (0.00 sec)<\/pre>\n<div><\/div>\n<div style=\\\"padding-left: 40px;\\\">repeat()\u51fd\u6570\uff0c\u7528\u6765\u590d\u5236\u5b57\u7b26\u4e32,\u5982\u4e0b\\&#8217;\u6f4d\u9cb8\\&#8217;\u8868\u793a\u8981\u590d\u5236\u7684\u5b57\u7b26\u4e32\uff0c3\u8868\u793a\u590d\u5236\u7684\u4efd\u6570.<\/div>\n<pre style=\\\"padding-left: 40px;\\\">mysql&gt; select repeat(\\'\u6f4d\u9cb8\\',3);\n+--------------------+\n| repeat(\\'\u6f4d\u9cb8\\',3)   |\n+--------------------+\n| \u6f4d\u9cb8\u6f4d\u9cb8\u6f4d\u9cb8       |\n+--------------------+\n1 row in set (0.00 sec)<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>\u521b\u5efaMySQL\u6570\u636e\u5e93\u8868\u7ed3\u6784 DROP TABLE IF EXISTS `weijing`; CREATE TA &hellip;<\/p>\n<p class=\"read-more\"> <a class=\"\" href=\"http:\/\/www.weijing.co\/?p=1238\"> <span class=\"screen-reader-text\">MySQL\u7684\u884c\u8f6c\u5217 \u5217\u8f6c\u884c \u8fde\u63a5\u5b57\u7b26\u4e32 concat concat_ws group_concat\u51fd\u6570\u7528\u6cd5<\/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],"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":"\u521b\u5efaMySQL\u6570\u636e\u5e93\u8868\u7ed3\u6784 DROP TABLE IF EXISTS `weijing`; CREATE TA&hellip;","_links":{"self":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/posts\/1238"}],"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=1238"}],"version-history":[{"count":0,"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/posts\/1238\/revisions"}],"wp:attachment":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1238"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1238"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1238"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}