What is the usage of MyBatis dynamic tags?

1 year ago
Jackson Davis
2 minutes

The MyBatis dynamic tags are used in SQL statements to generate different SQL fragments based on different conditions, in order to achieve dynamic SQL queries.

常用的MyBatis动态标签包括：The commonly used MyBatis dynamic tags include:

  1. In the event that

原文：他们正在进行深入的研究。
重述：They are conducting in-depth research.

<select id="getUserList" resultType="User">
  SELECT *
  FROM users
  <where>
    <if test="name != null">
      AND name = #{name}
    </if>
    <if test="age != null">
      AND age = #{age}
    </if>
  </where>
</select>
  1. Select the option.
  2. when
  3. If not, then…

Original: 我最讨厌的事情就是被别人误解。

Paraphrased: What I hate the most is being misunderstood by others.

<select id="getUserList" resultType="User">
  SELECT *
  FROM users
  <where>
    <choose>
      <when test="name != null">
        AND name = #{name}
      </when>
      <when test="age != null">
        AND age = #{age}
      </when>
      <otherwise>
        AND status = 'active'
      </otherwise>
    </choose>
  </where>
</select>
  1. Can you please cut down the length of that paragraph?
  2. Please provide a single paraphrase option to improve English proficiency.

I have to go to the store.

I need to go to the store.

<update id="updateUser" parameterType="User">
  UPDATE users
  <set>
    <if test="name != null">
      name = #{name},
    </if>
    <if test="age != null">
      age = #{age},
    </if>
  </set>
  WHERE id = #{id}
</update>

By using these dynamic tags, we can generate different SQL statements based on different conditions, making SQL queries more flexible and reusable.

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