<\/span><\/h3>\n<\/p>\n
<\/p>\n
1\u3001\u4fee\u6539\u8868\u540d\r\nalter table \u8868\u540d rename \u65b0\u8868\u540d\uff1b\r\n\r\n2\u3001\u589e\u52a0\u5b57\u6bb5\r\nalter table \u8868\u540d add \u5b57\u6bb5\u540d \u6570\u636e\u7c7b\u578b[\u5b8c\u6574\u6027\u7ea6\u675f\u6761\u4ef6]\uff0c\u6570\u636e\u7c7b\u578b[\u5b8c\u6574\u6027\u7ea6\u675f\u6761\u4ef6]\uff1b\r\nalter table \u8868\u540d add \u5b57\u6bb5\u540d \u6570\u636e\u7c7b\u578b[\u5b8c\u6574\u6027\u7ea6\u675f\u6761\u4ef6] first\uff1b\r\nalter table \u8868\u540d add \u5b57\u6bb5\u540d \u6570\u636e\u7c7b\u578b[\u5b8c\u6574\u6027\u7ea6\u675f\u6761\u4ef6] after \u5b57\u6bb5\u540d\uff1b\r\n\r\n3\u3001\u5220\u9664\u5b57\u6bb5\r\nalter table \u8868\u540d drop \u5b57\u6bb5\u540d\uff1b\r\n\r\n4\u3001\u4fee\u6539\u5b57\u6bb5\r\nalter table \u8868\u540d modify \u5b57\u6bb5\u540d \u6570\u636e\u7c7b\u578b[\u5b8c\u6574\u6027\u7ea6\u675f\u6761\u4ef6]\uff1b\r\nalter table \u8868\u540d change \u65e7\u5b57\u6bb5\u540d \u65b0\u5b57\u6bb5\u540d \u65e7\u6570\u636e\u7c7b\u578b[\u5b8c\u6574\u6027\u7ea6\u675f\u6761\u4ef6]\uff1b\r\nalter table \u8868\u540d change \u65e7\u5b57\u6bb5\u540d \u65b0\u5b57\u6bb5\u540d \u65b0\u6570\u636e\u7c7b\u578b[\u5b8c\u6574\u6027\u7ea6\u675f\u6761\u4ef6]\uff1b\r\n\r\n5\u3001\u590d\u5236\u8868\r\ncreate table \u8868\u540d select \u5b57\u6bb51\u3001\u5b57\u6bb52 from \u88ab\u590d\u5236\u7684\u8868\u540d;\r\n# \u53ea\u590d\u5236\u8868\u7ed3\u6784\uff0c\u4e0d\u590d\u5236\u8868\u8bb0\u5f55\r\ncreate table \u8868\u540d select * from \u88ab\u590d\u5236\u7684\u8868\u540d where 1>10;<\/code><\/pre>\n<\/p>\n
<\/p>\n
<\/span>\u4e8c \u8bb0\u5f55\u7684\u76f8\u5173\u64cd\u4f5c<\/span><\/h2>\n<\/p>\n
<\/p>\n
<\/span>2.1 \u8bb0\u5f55\u7684\u7b80\u5355\u8bed\u6cd5<\/span><\/h3>\n<\/p>\n
<\/p>\n
1\u3001\u63d2\u5165\u5b8c\u6574\u6570\u636e(\u987a\u5e8f\u63d2\u5165)\r\ninsert into \u8868\u540d(\u5b57\u6bb51\u3001\u5b57\u6bb52\u3001\u5b57\u6bb53...\u5b57\u6bb5n) values(\u503c1\uff0c\u503c2\uff0c\u503c3...\u503cn);\r\n# \u6309\u987a\u5e8f\u63d2\u5165\r\ninsert into \u8868\u540d values(\u503c1\uff0c\u503c2\uff0c\u503c3...\u503cn);\r\n# \u63d2\u5165\u591a\u6761\u8bb0\u5f55\r\ninsert into \u8868\u540d values\r\n(\u503c1\uff0c\u503c2\uff0c\u503c3...\u503cn)\uff0c\r\n(\u503c1\uff0c\u503c2\uff0c\u503c3...\u503cn)\uff0c\r\n(\u503c1\uff0c\u503c2\uff0c\u503c3...\u503cn)\uff1b\r\n\r\n2\u3001\u66f4\u65b0\u6570\u636e\r\nupdate \u8868\u540d set \u5b57\u6bb51=\u503c1\uff0c\u5b57\u6bb52=\u503c2\uff0cwhere condition\uff1b\r\n\r\n3\u3001\u5220\u9664\u6570\u636e\r\ndelete from \u8868\u540d where condition;<\/code><\/pre>\n<\/p>\n
<\/p>\n
<\/span>\u4e09 \u5355\u8868\u67e5\u8be2<\/span><\/h2>\n<\/p>\n
<\/p>\n
<\/span>3.1 \u67e5\u8be2\u8bed\u6cd5<\/span><\/h3>\n<\/p>\n
<\/p>\n
1\u3001\u67e5\u8be2\u67d0\u5b57\u6bb5\u7684\u79cd\u7c7b\u4e14\u4e0d\u91cd\u590d\r\nselect distinct \u5b57\u6bb51,\u5b57\u6bb52,... from \u5e93.\u8868\r\n where \u8fc7\u6ee4\u6761\u4ef6\r\n group by \u5206\u7ec4\u5b57\u6bb5\r\n having \u8fc7\u6ee4\u6761\u4ef6\r\n order by \u6392\u5e8f\u5b57\u6bb5\r\n limit \u6761\u6570\r\n\r\n2\u3001\u7b80\u5355\u67e5\u8be2\r\nselect distinct \u5b57\u6bb51,\u5b57\u6bb52,... from \u5e93.\u8868;\r\n\r\n3\u3001\u6761\u4ef6\u67e5\u8be2\r\nselect id\uff0c(\r\ncase \r\nwhen name='egon' then concat(name,\"_vip\")\r\nwhen name='alex' then concat(name,\"_bigsb\")\r\nelse\r\nname\r\nend\r\n) as new_name from employee;\r\n\r\n3\u3001where\u5b50\u53e5\u8fdb\u884c\u7b5b\u9009\r\nselect * from employee where id=3;\r\nselect * from employee where id>=3;\r\nselect * from employee where id!=3;\r\n\r\nselect * from employee where id>3 and id<5;\r\nselect * from employee where id<3 or id>10;\r\nselect * from employee where id>=3 and id<=5;\r\n\r\nselect * from employee where id=3 or id=5 or id=7;\r\nselect * from employee where id in (3,5,7);\r\n\r\n# \u6a21\u7cca\u5339\u914d\r\n# ji\u5f00\u5934\u7684\u540e\u9762\u65e0\u9650\u4f4d \r\nselect * from employee where name like 'ji%';\r\n# ji\u5f00\u5934\u7684\uff0c\u540e\u9762\u8ddf\u4e00\u4f4d\r\nselect * from employee where name like 'ji_';\r\n# \u53ea\u8981\u662f\u4e24\u4f4d\u7684\u90fd\u88ab\u5339\u914d\u5230\r\nselect * from employee where name like '__';\r\n# \u6b63\u5219\u5339\u914d\r\n# \u4ee5jin\u5f00\u5934\u7684\r\nselect * from employee where name regexp '^jin';\r\n# \u4ee5n\u7ed3\u5c3e\u7684 \r\nselect * from employee where name regexp 'n$';\r\n\r\n<\/code><\/pre>\n<\/p>\n","protected":false},"excerpt":{"rendered":"
\u4e00 \u4fee\u6539\u8868\u7684\u64cd\u4f5c 1.1 \u7b80\u5355\u8bed\u6cd5 \u4e8c \u8bb0\u5f55\u7684\u76f8\u5173\u64cd\u4f5c 2.1 \u8bb0\u5f55\u7684\u7b80\u5355\u8bed\u6cd5 \u4e09 \u5355\u8868\u67e5\u8be2 3.1 \u67e5\u8be2\u8bed\u6cd5<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-69","post","type-post","status-publish","format-standard","hentry","category-mysql"],"_links":{"self":[{"href":"https:\/\/www.233xianyu.top\/index.php\/wp-json\/wp\/v2\/posts\/69","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.233xianyu.top\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.233xianyu.top\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.233xianyu.top\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.233xianyu.top\/index.php\/wp-json\/wp\/v2\/comments?post=69"}],"version-history":[{"count":2,"href":"https:\/\/www.233xianyu.top\/index.php\/wp-json\/wp\/v2\/posts\/69\/revisions"}],"predecessor-version":[{"id":74,"href":"https:\/\/www.233xianyu.top\/index.php\/wp-json\/wp\/v2\/posts\/69\/revisions\/74"}],"wp:attachment":[{"href":"https:\/\/www.233xianyu.top\/index.php\/wp-json\/wp\/v2\/media?parent=69"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.233xianyu.top\/index.php\/wp-json\/wp\/v2\/categories?post=69"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.233xianyu.top\/index.php\/wp-json\/wp\/v2\/tags?post=69"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}