MyBatis动态添加—trim标签

做添加时,部分字段有值,没值的字段不添加,这就是动态添加,使用 trim 标签就可以实现。

<insert id="insertSysUser" parameterType="com.mydemo.entity.SysUser">
        insert into sys_user
        <trim prefix="(" suffix=")" suffixOverrides=",">
            <if test="id != null and id != ''">
                id,
            if>
            <if test="username != null and username != ''">
                username,
            if>
            <if test="realName != null and realName != ''">
                real_name,
            if>
            <if test="idcard != null and idcard != ''">
                idcard,
            if>
            create_time
        trim>
        <trim prefix="values(" suffix=")" suffixOverrides=",">
               <if test="id != null and id != ''">
                #{id, jdbcType = VARCHAR},
            if>
            <if test="username != null and username != ''">
                #{username, jdbcType = VARCHAR},
            if>
            <if test="realName != null and realName != ''">
                #{realName, jdbcType = VARCHAR},
            if>
            <if test="idcard != null and idcard != ''">
                #{idcard, jdbcType = VARCHAR},
            if>
            now()
        trim>
    insert>

最终结果:insert into sys_user ( id, username, real_name, idcard, create_time ) values( ?, ?, ?, ?, now() ) 

trim标签属性含义:

属性 描述
prefix 给sql语句拼接的前缀
suffix 给sql语句拼接的后缀
prefixesToOverride 去除sql语句前面的关键字或者字符,该关键字或者字符由prefixesToOverride属性指定,假设该属性指定为”AND”,当sql语句的开头为”AND”,trim标签将会去除该”AND”
suffixesToOverride 去除sql语句后面的关键字或者字符,该关键字或者字符由suffixesToOverride属性指定

 

 

 

 

 

 

转载于:https://www.cnblogs.com/jingyi17/p/10273181.html

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