mybatis series summary

Mybatis fuzzy query three common methods recorded in MySQL

Taking MySQL database as an example (different databases, some may not support)
there are three commonly used fuzzy query methods:
1. Directly use % to concatenate strings, such as '%'#{name}'%' or "%"#{name }"%", either single or double quotes are fine.
2. Use the concat (str1, str2) function to splice
3. Use the bind tag of mybatis to create a new tag for mapping sql
in the userMapper.xml file:

<!-- 模糊查询的常用的3种方式 -->
<select id="getUsersByFuzzyQuery" parameterType="User" resultType="User">
    select <include refid="columns"/> from users
    <where>
        <!--
            方法一: 直接使用 % 拼接字符串 
            注意:此处不能写成  "%#{name}%" ,#{name}就成字符串的一部分,
            会发生这样一个异常: The error occurred while setting parameters,
            应该写成: "%"#{name}"%",即#{name}是一个整体,前后加上%
        -->
        <if test="name != null">
            name like "%"#{name}"%"
        </if>
        <!--方法二: 使用concat(str1,str2)函数将两个参数连接 -->
        <if test="phone != null">
            and phone like concat(concat("%",#{phone}),"%")
        </if>
        <!--方法三: 使用 bind 标签，对字符串进行绑定，然后对绑定后的字符串使用 like 关键字进行模糊查询 -->
        <if test="email != null">
            <bind name="pattern" value="'%'+email+'%'"/>
            and email like #{pattern}
        </if>
    </where>
</select>