mybatis-plus自带QueryWrapper自定义sql实现复杂查询实例详解

    LambdaQueryWrapper<xxxDO> queryWrapper = Wrappers.lambdaQuery();
    queryWrapper.select(xxxDO::getName, DO::getId);
    queryWrapper.eq(xxxDO::getDeleteFlag, 0);
    queryWrapper.eq(xxxDO::getStatus, 0);
    queryWrapper.groupBy(xxxDO::getName);
    List<xxxDO> list = getBaseMapper().selectList(queryWrapper);

    LambdaQueryWrapper<xxxDO> queryWrapper = new QueryWrapper<xxxDO>()
            .select("sex, ifnull(count(id), 0) AS num, CASE WHEN sex = 1 THEN '男' WHEN sex = 0 THEN '女' ELSE '未知' END AS sexStr").lambda();
    queryWrapper.eq(xxxDO::getStatus, 0);
    queryWrapper.groupBy(xxxDO::getSex);
    List<Map<String, Object>> mapList = getBaseMapper().selectMaps(queryWrapper);
    Map<String, String> registerNumMap = new HashMap<>(mapList.size());
    for (Map<String, Object> map : mapList) {
        String key = String.valueOf(map.get("sexStr"));
        String num = String.valueOf(map.get("num"));
        registerNumMap.put(key, num);
    }

    queryWrapper.apply("INET_ATON(qsip) <= INET_ATON({0})", ipQuery);
    queryWrapper.apply("INET_ATON(zzip) >= INET_ATON({0})", ipQuery);

        queryWrapper.last(" order by id asc");
        queryWrapper.last("limit 1");

        // last也可以追加limit 这里用page接口
 
        IPage<Entity> buildPage = new Page<>(0, 200);
        // ServiceImpl的page调用的是baseMapper的selectPage, getBaseMapper().selectPage()
        IPage<Entity> page = page(buildPage, queryWrapper);

public static final String SQL_RULES_COLUMN = "SQL_RULES_COLUMN";

private static final String BEGIN = "_begin";  // 字段范围查询开始标识
private static final String END = "_end";  // 字段范围查询结束标识
private static final String STAR = "*";  // 字段模糊查询标识
private static final String COMMA = ",";
private static final String NOT_EQUAL = "!";

   <select id="listAll" resultType="net.zazn.modules.discipline.entity.Emdj">
       select id,lffh,xm,jsh,szrq,emlx,spzt,gjmj,flag,jlzt
       from emdj
       <where>${ew.customSqlSegment}</where>
   </select>