{"id":14306,"date":"2023-12-04T01:23:05","date_gmt":"2023-12-03T17:23:05","guid":{"rendered":"https:\/\/wx.kaifamiao.info\/?p=14306"},"modified":"2023-12-04T01:23:59","modified_gmt":"2023-12-03T17:23:59","slug":"mybatis-dong-tai-sql","status":"publish","type":"post","link":"http:\/\/wx.kaifamiao.info\/index.php\/2023\/12\/04\/mybatis-dong-tai-sql\/","title":{"rendered":"MyBatis \u52a8\u6001 SQL\uff1f"},"content":{"rendered":"

MyBatis \u4e2d\u7684\u52a8\u6001 SQL \u5141\u8bb8\u6839\u636e\u6761\u4ef6\u6765\u52a8\u6001\u6784\u5efa SQL \u67e5\u8be2\u8bed\u53e5\uff0c\u4ece\u800c\u5b9e\u73b0\u66f4\u7075\u6d3b\u7684 SQL \u64cd\u4f5c\u3002\u52a8\u6001 SQL \u4e3b\u8981\u5305\u62ec\u4ee5\u4e0b\u51e0\u4e2a\u65b9\u9762\uff1a<\/p>\n

1. <if><\/code> \u5143\u7d20\uff1a<\/h3>\n
<select id=\"getUser\" parameterType=\"map\" resultType=\"User\">\n    SELECT * FROM users\n    <where>\n        <if test=\"name != null\">\n            AND name = #{name}\n        <\/if>\n        <if test=\"age != null\">\n            AND age = #{age}\n        <\/if>\n    <\/where>\n<\/select>\n<\/code><\/pre>\n
<if><\/code> \u5143\u7d20\u7528\u4e8e\u6761\u4ef6\u5224\u65ad\uff0c\u6839\u636e\u6761\u4ef6\u52a8\u6001\u62fc\u63a5 SQL \u8bed\u53e5\u3002<\/p>\n
2. <choose><\/code>, <when><\/code>, <otherwise><\/code> \u5143\u7d20\uff1a<\/h3>\n
<select id=\"getUser\" parameterType=\"map\" resultType=\"User\">\n    SELECT * FROM users\n    <where>\n        <choose>\n            <when test=\"condition == 'A'\">\n                AND column = 'A'\n            <\/when>\n            <when test=\"condition == 'B'\">\n                AND column = 'B'\n            <\/when>\n            <otherwise>\n                AND column = 'C'\n            <\/otherwise>\n        <\/choose>\n    <\/where>\n<\/select>\n<\/code><\/pre>\n
<choose><\/code> \u5143\u7d20\u7c7b\u4f3c\u4e8e Java \u4e2d\u7684 switch\uff0c\u6839\u636e\u6761\u4ef6\u9009\u62e9\u6267\u884c\u5176\u4e2d\u7684\u4e00\u4e2a\u5206\u652f\u3002<\/p>\n
3. <foreach><\/code> \u5143\u7d20\uff1a<\/h3>\n
<select id=\"getUsersByIds\" parameterType=\"map\" resultType=\"User\">\n    SELECT * FROM users WHERE id IN\n    <foreach collection=\"ids\" item=\"id\" open=\"(\" separator=\",\" close=\")\">\n        #{id}\n    <\/foreach>\n<\/select>\n<\/code><\/pre>\n
<foreach><\/code> \u5143\u7d20\u7528\u4e8e\u904d\u5386\u96c6\u5408\uff0c\u52a8\u6001\u751f\u6210 SQL \u7684 IN \u5b50\u53e5\u3002<\/p>\n
4. <trim><\/code>, <set><\/code>, <where><\/code> \u5143\u7d20\uff1a<\/h3>\n
<update id=\"updateUser\" parameterType=\"User\">\n    UPDATE users\n    <set>\n        <if test=\"name != null\">\n            name = #{name},\n        <\/if>\n        <if test=\"age != null\">\n            age = #{age},\n        <\/if>\n    <\/set>\n    WHERE id = #{id}\n<\/update>\n<\/code><\/pre>\n
\u8fd9\u4e9b\u5143\u7d20\u7528\u4e8e\u63a7\u5236 SQL \u8bed\u53e5\u4e2d\u7a7a\u767d\u5b57\u7b26\u7684\u53bb\u9664\uff0c\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u9017\u53f7\u6216 AND \u8fde\u63a5\u3002<\/p>\n
\u52a8\u6001 SQL \u53ef\u4ee5\u6839\u636e\u4e0d\u540c\u6761\u4ef6\u751f\u6210\u4e0d\u540c\u7684 SQL \u8bed\u53e5\uff0c\u4f7f\u5f97 SQL \u67e5\u8be2\u66f4\u52a0\u7075\u6d3b\uff0c\u80fd\u591f\u6839\u636e\u5b9e\u9645\u9700\u6c42\u52a8\u6001\u6784\u5efa\u67e5\u8be2\u6761\u4ef6\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
MyBatis \u4e2d\u7684\u52a8\u6001 SQL \u5141\u8bb8\u6839\u636e\u6761\u4ef6\u6765\u52a8\u6001\u6784\u5efa SQL \u67e5\u8be2\u8bed\u53e5\uff0c\u4ece\u800c\u5b9e\u73b0\u66f4\u7075\u6d3b\u7684 SQL \u64cd\u4f5c\u3002\u52a8 […]<\/p>\n","protected":false},"author":11,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[113],"tags":[],"class_list":["post-14306","post","type-post","status-publish","format-standard","hentry","category-mybatis"],"_links":{"self":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/14306","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/comments?post=14306"}],"version-history":[{"count":1,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/14306\/revisions"}],"predecessor-version":[{"id":14307,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/14306\/revisions\/14307"}],"wp:attachment":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/media?parent=14306"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/categories?post=14306"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/tags?post=14306"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}