mybatis trim

MyBatis provides a useful feature called "trim" that allows you to remove unnecessary whitespace from the beginning or end of a SQL query. The "trim" element is typically used within a "where" or "set" clause to dynamically generate the query based on certain conditions.

Here's an example of how to use the "trim" element in MyBatis:

<trim prefix="WHERE" prefixOverrides="AND |OR ">
  <if test="name != null">
    name = #{name}
  </if>
  <if test="age != null">
    AND age = #{age}
  </if>
  <if test="city != null">
    AND city = #{city}
  </if>
</trim>

In this example, the "trim" element is used to remove unnecessary "AND" or "OR" prefixes if the preceding condition is not met. This helps to generate a cleaner and more efficient SQL query.

You can customize the "prefix" attribute to specify the desired prefix for the trimmed content. The "prefixOverrides" attribute is used to specify the prefixes that should be removed if a condition is not met. Multiple prefixes can be specified by separating them with a pipe (|) character.

Hope this helps! Let me know if you have any further questions.