add post

coder-lida · coder-lida · commit 7cf82d21e06a · 2020-03-21T15:26:47.000+08:00
diff --git a/source/_posts/Mybatis if标签判断数字大小.md b/source/_posts/Mybatis if标签判断数字大小.md
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+title: Mybatis if标签判断数字大小
+tags:
+  - MyBatis
+categories:
+  - Dev
+  - Java
+date: 2020-03-18 14:01:00
+cover: true
+
+---
+
+![](http://q6pznk9ej.bkt.clouddn.com/fish.jpg)
+<!-- more -->
+## if标签语法
+```
+<select...>
+  SQL语句1
+  <if test="条件表达式">
+     SQL语句2
+  </if>
+</select>
+```
+
+## 条件表达式中大于号小于号用 gt,lt
+```
+<if test="num gt 0">...</if>
+
+<if test="num lt 0">...</if>
+```
+
+## mapper
+```
+List<ZftjHalf> selectByAreaIdAndYear(@Param("areaId") String areaId,
+                                     @Param("year") String year,
+                                     @Param("level") int level);
+```
+
+##xml
+```
+  <select id="selectByAreaIdAndYear" resultType="com.zftdata.nyzft.entity.ZftjHalf">
+    select * from ZFTJ_HALF
+    where FILLING_TIME LIKE CONCAT(#{year},'%')
+    <if test="level lt 3">
+      and AREA_ID_PID =#{areaId}
+    </if>
+    <if test="level gt 2">
+      and AREA_ID =#{areaId}
+    </if>
+    <if test="level == 4">
+      and AREA_ID =#{areaId}
+    </if>
+  </select>
+```
