请问是如何进行搜索的，jsp和java，调用的layui框架

Question

                    <select name="userId" lay-filter="aihao" lay-search="" clear>
                        <option value="-1">全部</option>
                        <c:forEach items="${users}" var="item">
                            <option value="${item.id}" ${ item.id == obj.userId ? "selected" : ""}>${item.username}</option>
                        </c:forEach>
                    </select>

```java
        String sql2 = "SELECT * FROM user WHERE 1=1 and is_delete = 0 ";
        List<User> users = userService.listBySqlReturnEntity(sql2);
        model.addAttribute("users",users);
        String sql = "SELECT * FROM daily_inspection WHERE 1=1 ";
        if(!isEmpty(dailyInspection.getUserId()) && dailyInspection.getUserId() != -1){//这一行非常不理解！！！！
            sql += " and user_id = "+dailyInspection.getUserId();
        }

Answer 1

sql 语句拼接，如果当前 dailyInspection.getUserId() 不是空值并且不为-1，那么执行
SELECT * FROM daily_inspection WHERE 1=1 and user_id = ‘ 你当前的dailyInspection.getUserId() ’ 也就是根据用户id查询daily_inspection

否则执行语句
SELECT * FROM daily_inspection WHERE 1=1
查询全部的daily_inspection