MySQL和mybatis查询相关

0.mybatis的xml文件头

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >

 <mapper namespace="me.gacl.dao.UserMapper" >


 </mapper>

1.mybatis 中 foreach collection的用法

<select id="dynamicForeachTest" parameterType="java.util.List" resultType="Blog">
           select * from t_blog where id in
        <foreach collection="list" index="index" item="item" open="(" separator="," close=")">
                #{item}       
        </foreach>    
    </select>

2.mybatis批量插入更新

　　方法一：

<update id="batchUpdate" parameterType="java.util.List"> 
      <foreach separator=";" index="index" item="item" collection="list" close="" open=""> 
      update sys_group set level = #{item.level,jdbcType=INTEGER}
       where group_id = #{item.groupId,jdbcType=INTEGER}
      </foreach> 
  </update>

　　方法二：

<update id="batchUpdate1" parameterType="java.util.List"> 
     
      update sys_group set level = null where level in
       <foreach separator="," index="index" item="item" collection="list" close=")" open="("> 
         #{item}
      </foreach> 
  </update>

3.mybatis映射

<resultMap id="BaseResultMap" type="me.gacl.domain.User" >
      <id column="user_id" property="userId" jdbcType="CHAR" />
      <result column="user_name" property="userName" jdbcType="VARCHAR" />
      <result column="user_birthday" property="userBirthday" jdbcType="DATE" />
      <result column="user_salary" property="userSalary" jdbcType="DOUBLE" />
    </resultMap>
   <sql id="Base_Column_List" >
     user_id, user_name, user_birthday, user_salary
   </sql>

4.mybatis查询select

<select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.String" >
     select 
     <include refid="Base_Column_List" />
     from t_user
     where user_id = #{userId,jdbcType=CHAR}
   </select>

5.mybatis删除delete

<delete id="deleteByPrimaryKey" parameterType="java.lang.String" >
     delete from t_user
     where user_id = #{userId,jdbcType=CHAR}
   </delete>

6.mybatis插入insert

　　一：

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 <insert id="insert" parameterType="me.gacl.domain.User" >
     insert into t_user (user_id, user_name, user_birthday, 
       user_salary)
     values (#{userId,jdbcType=CHAR}, #{userName,jdbcType=VARCHAR}, #{userBirthday,jdbcType=DATE}, 
       #{userSalary,jdbcType=DOUBLE})
   </insert>

　　二：

 <insert id="insertSelective" parameterType="me.gacl.domain.User" >
     insert into t_user
     <trim prefix="(" suffix=")" suffixOverrides="," >
       <if test="userId != null" >
         user_id,
       </if>
       <if test="userName != null" >
         user_name,
       </if>
       <if test="userBirthday != null" >
         user_birthday,
       </if>
       <if test="userSalary != null" >
         user_salary,
       </if>
     </trim>
     <trim prefix="values (" suffix=")" suffixOverrides="," >
       <if test="userId != null" >
         #{userId,jdbcType=CHAR},
       </if>
       <if test="userName != null" >
         #{userName,jdbcType=VARCHAR},
       </if>
       <if test="userBirthday != null" >
         #{userBirthday,jdbcType=DATE},
       </if>
       <if test="userSalary != null" >
         #{userSalary,jdbcType=DOUBLE},
       </if>
     </trim>
   </insert>

7.mybatis更新update

　　一：

<update id="updateByPrimaryKey" parameterType="me.gacl.domain.User" >
     update t_user
     set user_name = #{userName,jdbcType=VARCHAR},
       user_birthday = #{userBirthday,jdbcType=DATE},
       user_salary = #{userSalary,jdbcType=DOUBLE}
     where user_id = #{userId,jdbcType=CHAR}
   </update>

　　二：

<update id="updateByPrimaryKeySelective" parameterType="me.gacl.domain.User" >
     update t_user
     <set >
       <if test="userName != null" >
         user_name = #{userName,jdbcType=VARCHAR},
       </if>
       <if test="userBirthday != null" >
         user_birthday = #{userBirthday,jdbcType=DATE},
       </if>
       <if test="userSalary != null" >
         user_salary = #{userSalary,jdbcType=DOUBLE},
       </if>
     </set>
     where user_id = #{userId,jdbcType=CHAR}
   </update>

MySQL和mybatis查询相关

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