MyBatis IN Clause Usage in XML

1 year ago
Jackson Davis
1 minute

In MyBatis XML files, you can use the tag to achieve functionality similar to the IN operator in SQL. This tag is used to iterate through elements in a collection (such as a List, Array, etc.) and pass each element as a parameter to a specified SQL statement.

Here is an example showing how to use the tag in MyBatis XML files to achieve the functionality of the IN operator.

<select id="selectUsersByIds" parameterType="map" resultType="User">
    SELECT * 
    FROM users
    WHERE id IN 
    <foreach collection="userIds" item="id" open="(" separator="," close=")">
        #{id}
    </foreach>
</select>

In the example above, the tag iterates through a collection called userIds, assigning each element from the collection to the id variable during each iteration. The value of the id variable is then passed as a parameter to the #{id} placeholder in the SQL statement. The resulting SQL statement dynamically generates the IN operator based on the elements in the userIds collection.

The tag can easily achieve query operations for multiple parameters, avoiding manual concatenation of SQL statements, and improving the readability and maintainability of code.

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