mybatis else

MyBatis中的<if>标签可以用于条件判断，而<otherwise>标签则是<if>标签的补充，用于处理不满足条件的情况。当<if>标签中的条件不成立时，<otherwise>标签中的SQL语句会被执行。下面是一个示例：

<select id="getUserList" resultType="User">
  SELECT * FROM user
  <where>
    <if test="name != null">
      AND name = #{name}
    </if>
    <otherwise>
      AND age = #{age}
    </otherwise>
  </where>
</select>

在上面的示例中，如果传入的参数中包含name，则会执行AND name = #{name}这条SQL语句；否则会执行AND age = #{age}这条SQL语句。

相关问题

mybatis else 表达式

MyBatis的`<otherwise>`标签是用于在`<choose>`语句中定义默认条件的。`<choose>`语句中可以有多个`<when>`标签，每个`<when>`标签定义一个条件，如果这些条件都不满足，就会执行`<otherwise>`标签中的语句。

以下是一个示例：

<select id="findOrders" parameterType="map" resultType="Order">
  SELECT * FROM ORDERS
  WHERE 1=1
  <choose>
    <when test="status != null">
      AND STATUS = #{status}
    </when>
    <when test="startDate != null and endDate != null">
      AND ORDER_DATE BETWEEN #{startDate} AND #{endDate}
    </when>
    <otherwise>
      AND ORDER_DATE >= DATEADD(month, -1, GETDATE())
    </otherwise>
  </choose>
</select>

在这个例子中，如果传入了`status`参数，将按照该状态查询订单；如果传入了`startDate`和`endDate`参数，将按照订单日期范围查询订单；否则将查询最近一个月的订单。如果没有`<otherwise>`标签，那么当所有条件都不满足时，将不会有任何结果返回。

mybatis elseif

MyBatis does not have a specific "elseif" statement like other programming languages or frameworks. Instead, you can use the "choose" statement in MyBatis to achieve similar functionality.

The "choose" statement in MyBatis is used to evaluate multiple conditions and execute different SQL statements based on the result. It consists of "when" and "otherwise" elements.

Here's an example of how you can use the "choose" statement in MyBatis to replace an "elseif" condition:

<select id="getUser" resultType="User">
  SELECT *
  FROM users
  WHERE
    <choose>
      <when test="param == 'admin'">
        role = 'admin'
      </when>
      <when test="param == 'manager'">
        role = 'manager'
      </when>
      <otherwise>
        role = 'user'
      </otherwise>
    </choose>
</select>

In the above example, the SQL query will check the value of the "param" parameter and execute different conditions based on its value. If "param" is equal to "admin", it will search for users with the role 'admin'. If "param" is equal to 'manager', it will search for users with the role 'manager'. Otherwise, it will search for users with the role 'user'.

Remember to adjust the conditions and values based on your specific requirements.