{"id":2808,"date":"2023-04-27T13:42:47","date_gmt":"2023-04-27T05:42:47","guid":{"rendered":"https:\/\/hsin-life.com\/?p=2808"},"modified":"2023-04-27T13:42:48","modified_gmt":"2023-04-27T05:42:48","slug":"mybatis-%e4%b8%ad%e6%9b%bf%e4%bb%a3-where-11-%e7%9a%84%e5%8b%95%e6%85%8b-sql-%e5%af%a6%e8%b8%90","status":"publish","type":"post","link":"https:\/\/hsin-life.com\/archives\/2808","title":{"rendered":"MyBatis \u4e2d\u66ff\u4ee3 WHERE 1=1 \u7684\u52d5\u614b SQL \u5be6\u8e10"},"content":{"rendered":"\n

\u5728 SQL \u8a9e\u6cd5\u4e2d\uff0cWHERE 1=1 \u7684\u4f7f\u7528\u4e3b\u8981\u662f\u70ba\u4e86\u52d5\u614b SQL \u62fc\u63a5\u548c\u907f\u514d\u8a9e\u6cd5\u932f\u8aa4\u3002<\/p>\n\n\n\n

\u7136\u800c\uff0c\u5728\u67d0\u4e9b\u60c5\u5883\u4e0b\uff0c\u4f7f\u7528 WHERE 1=1 \u4e26\u4e0d\u662f\u6700\u4f73\u5be6\u8e10\u3002<\/p>\n\n\n\n

\u672c\u6587\u5c07\u4ecb\u7d39\u5728 MyBatis \u4e2d\uff0c\u5982\u4f55\u4f7f\u7528\u52d5\u614b SQL \u529f\u80fd\u66ff\u4ee3 WHERE 1=1 \u7684\u5beb\u6cd5\uff0c\u4ee5\u66f4\u9748\u6d3b\u5730\u69cb\u5efa SQL \u8a9e\u53e5\u3002<\/p>\n\n\n\n

MyBatis \u63d0\u4f9b\u4e86\u591a\u7a2e\u52d5\u614b SQL \u6a19\u7c64\uff0c\u53ef\u4ee5\u8b93\u60a8\u5728 XML \u6620\u5c04\u6587\u4ef6\u4e2d\u7de8\u5beb\u66f4\u9748\u6d3b\u7684 SQL \u8a9e\u53e5\u3002<\/p>\n\n\n\n

\u4ee5\u4e0b\u662f\u4e00\u4e9b MyBatis \u52d5\u614b SQL \u7684\u7528\u6cd5\uff1a<\/p>\n\n\n\n

<if><\/code> \u6a19\u7c64\uff1a<if><\/code> \u6a19\u7c64\u5141\u8a31\u60a8\u6839\u64da\u689d\u4ef6\u63d2\u5165 SQL \u7247\u6bb5\u3002\u4f8b\u5982\uff1a<\/p>\n\n\n\n

<select id=\"findUsers\" resultType=\"User\">\r\n  SELECT * FROM user\r\n  <where>\r\n    <if test=\"username != null\">\r\n      AND username = #{username}\r\n    <\/if>\r\n    <if test=\"email != null\">\r\n      AND email = #{email}\r\n    <\/if>\r\n  <\/where>\r\n<\/select>\r\n<\/code><\/pre>\n\n\n\n
\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0cMyBatis \u6703\u6839\u64da username<\/code> \u548c email<\/code> \u662f\u5426\u70ba\u7a7a\u4f86\u52d5\u614b\u62fc\u63a5 SQL \u8a9e\u53e5\u3002<\/p>\n\n\n\n
\u9019\u6a23\u5c31\u907f\u514d\u4e86\u4f7f\u7528 WHERE 1=1 \u7684\u5beb\u6cd5\u3002<\/p>\n\n\n\n
<choose><\/code>\u3001<when><\/code> \u548c <otherwise><\/code> \u6a19\u7c64\uff1a\u9019\u4e9b\u6a19\u7c64\u5141\u8a31\u60a8\u6839\u64da\u689d\u4ef6\u9078\u64c7\u4e0d\u540c\u7684 SQL \u7247\u6bb5\u3002<\/p>\n\n\n\n
\u4f8b\u5982\uff1a<\/p>\n\n\n\n
<select id=\"findUsers\" resultType=\"User\">\r\n  SELECT * FROM user\r\n  <where>\r\n    <choose>\r\n      <when test=\"username != null\">\r\n        username = #{username}\r\n      <\/when>\r\n      <when test=\"email != null\">\r\n        email = #{email}\r\n      <\/when>\r\n      <otherwise>\r\n        1 = 1\r\n      <\/otherwise>\r\n    <\/choose>\r\n  <\/where>\r\n<\/select>\r\n<\/code><\/pre>\n\n\n\n
\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0cMyBatis \u6703\u6839\u64da username<\/code> \u548c email<\/code> \u7684\u503c\u9078\u64c7\u76f8\u61c9\u7684 SQL \u7247\u6bb5\uff0c\u5982\u679c\u5169\u8005\u90fd\u70ba\u7a7a\uff0c\u5247\u4f7f\u7528 1=1 \u4f5c\u70ba\u689d\u4ef6\u3002<\/p>\n\n\n\n
\u901a\u904e\u4f7f\u7528 MyBatis \u7684\u52d5\u614b SQL \u529f\u80fd\uff0c\u60a8\u53ef\u4ee5\u66f4\u9748\u6d3b\u5730\u69cb\u5efa SQL \u8a9e\u53e5\uff0c\u540c\u6642\u907f\u514d WHERE 1=1 \u7684\u5beb\u6cd5\u3002<\/p>\n\n\n\n
\u9664\u4e86\u4e0a\u8ff0\u4ecb\u7d39\u7684 <if><\/code>\u3001<choose><\/code>\u3001<when><\/code> \u548c <otherwise><\/code> \u6a19\u7c64\uff0cMyBatis \u9084\u63d0\u4f9b\u4e86\u5176\u4ed6\u52d5\u614b SQL \u6a19\u7c64\uff0c\u5982 <trim><\/code>\u3001<set><\/code> \u548c <foreach><\/code> \u7b49\uff0c\u4ee5\u6eff\u8db3\u66f4\u591a\u7684\u67e5\u8a62\u9700\u6c42\u3002<\/p>\n\n\n\n
\u4f8b\u5982\uff0c\u4f7f\u7528 <trim><\/code> \u6a19\u7c64\u53ef\u4ee5\u5728\u52d5\u614b\u751f\u6210\u7684 SQL \u4e2d\u81ea\u52d5\u53bb\u9664\u591a\u9918\u7684\u9017\u865f\u6216 AND\/OR \u689d\u4ef6\uff1a<\/p>\n\n\n\n
<update id=\"updateUser\" parameterType=\"User\">\r\n  UPDATE user\r\n  <set>\r\n    <if test=\"username != null\">\r\n      username = #{username},\r\n    <\/if>\r\n    <if test=\"email != null\">\r\n      email = #{email},\r\n    <\/if>\r\n  <\/set>\r\n  WHERE id = #{id}\r\n<\/update>\r\n<\/code><\/pre>\n\n\n\n
\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u5982\u679c username<\/code> \u548c email<\/code> \u90fd\u4e0d\u70ba\u7a7a\uff0c\u5247\u751f\u6210\u7684 SQL \u8a9e\u53e5\u6703\u81ea\u52d5\u53bb\u9664\u6700\u5f8c\u4e00\u500b\u9017\u865f\u3002<\/p>\n\n\n\n
\u7e3d\u4e4b\uff0cMyBatis \u7684\u52d5\u614b SQL \u529f\u80fd\u70ba\u60a8\u63d0\u4f9b\u4e86\u66f4\u9748\u6d3b\u3001\u6613\u65bc\u7dad\u8b77\u7684 SQL \u8a9e\u53e5\u7de8\u5beb\u65b9\u5f0f\uff0c\u907f\u514d\u4e86\u4f7f\u7528 WHERE 1=1 \u9019\u6a23\u7684\u6280\u5de7\u3002<\/p>\n\n\n\n
\u5728\u5be6\u969b\u958b\u767c\u4e2d\uff0c\u60a8\u53ef\u4ee5\u6839\u64da\u9700\u6c42\u9078\u64c7\u9069\u5408\u7684\u52d5\u614b SQL \u6a19\u7c64\uff0c\u4ee5\u63d0\u9ad8 SQL \u8a9e\u53e5\u7684\u53ef\u8b80\u6027\u548c\u6548\u80fd\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u672c\u6587\u4ecb\u7d39\u4e86\u5728\u4f7f\u7528 MyBatis \u6642\uff0c\u5982\u4f55\u5229\u7528\u52d5\u614b SQL \u529f\u80fd\u66ff\u4ee3 WHERE 1=1 \u7684\u5beb\u6cd5\uff0c\u4e26\u901a\u904e\u5be6\u4f8b\u8aaa\u660e\u5982\u4f55\u66f4\u9748\u6d3b\u5730\u69cb\u5efa SQL \u8a9e\u53e5\u3002<\/p>\n","protected":false},"author":1,"featured_media":2809,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[145],"tags":[704,705,706,708,707],"aioseo_notices":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"https:\/\/i0.wp.com\/hsin-life.com\/wp-content\/uploads\/2023\/04\/pexels-photo-546819-3.jpeg?fit=1880%2C1249&ssl=1","jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/hsin-life.com\/wp-json\/wp\/v2\/posts\/2808"}],"collection":[{"href":"https:\/\/hsin-life.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hsin-life.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hsin-life.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/hsin-life.com\/wp-json\/wp\/v2\/comments?post=2808"}],"version-history":[{"count":0,"href":"https:\/\/hsin-life.com\/wp-json\/wp\/v2\/posts\/2808\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hsin-life.com\/wp-json\/wp\/v2\/media\/2809"}],"wp:attachment":[{"href":"https:\/\/hsin-life.com\/wp-json\/wp\/v2\/media?parent=2808"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hsin-life.com\/wp-json\/wp\/v2\/categories?post=2808"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hsin-life.com\/wp-json\/wp\/v2\/tags?post=2808"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}