例子有点憨,将就看
<choose> <when test="id = 1"> and id = 2 </when> <when test="id = 2"> and id = 3 </when> <otherwise> and id is null </otherwise> </choose>
choose中的when会不会匹配多个? 不会,从上到下判断,匹配到一个之后,其他的就不会匹配了