MyBatis 动态SQL trim

select * from user<trim prefix="WHERE" prefixoverride="AND |OR"><if test="name != null and name.length()>0"> AND name=#{name}</if><if test="gender != null and gender.length()>0"> AND gender=#{gender}</if></trim>假如说name和gender的值都不为null的话打印的SQL为：select * from user where name = 'xx'and gender = 'xx'prefix：前缀prefixoverride：去掉第一个and或者是or

update user<trim prefix="set" suffixoverride="," suffix=" where id = #{id} "><if test="name != null and name.length()>0"> name=#{name} , </if><if test="gender != null and gender.length()>0"> AND gender=#{gender} ,  </if></trim>假如说name和gender的值都不为null的话打印的SQL为：update user set name='xx' , gender='xx'where id='x'suffixoverride：去掉最后一个逗号（也可以是其他的标记，就像是上面前缀中的and一样）suffix：后缀