how dynamic mybatis search cloums

MyBatis allows dynamic searching of columns by using the <where> element in the SQL statement. This element is used to dynamically build the WHERE clause of the SQL statement based on the conditions specified in the query.

For example, consider the following SQL statement:

SELECT * FROM users WHERE name = #{name} AND age = #{age}

If we want to make the age condition optional, we can use MyBatis' dynamic SQL feature to achieve this. We would modify the SQL statement as follows:

SELECT * FROM users
<where>
    <if test="name != null">
        AND name = #{name}
    </if>
    <if test="age != null">
        AND age = #{age}
    </if>
</where>

In this example, the <where> element is used to encapsulate the dynamic conditions. The <if> element is used to conditionally include the age condition in the WHERE clause only if the age parameter is not null.

This allows us to build dynamic SQL statements based on the search criteria provided by the user.