called_number IN ( SELECT called_number FROM call_records WHERE call_start_time >= DATE_SUB(NOW(), INTERVAL 2 HOUR) AND caller_number NOT LIKE '0%' GROUP BY called_number HAVING COUNT(DISTINCT caller_number) >= 5 )分析这段sql
时间: 2024-04-01 11:36:11 浏览: 86
好的,这段 SQL 是使用了子查询,大致的意思是:
首先,从 `call_records` 表中选取满足以下条件的 `called_number` 列:对于 `call_start_time` 在过去两小时之内的通话记录,且 `caller_number` 不以 `0` 开头,然后按照 `called_number` 进行分组,最后筛选出满足被不少于 5 个不同的 `caller_number` 所拨打过的号码。
然后,将满足条件的 `called_number` 列作为子查询的结果,用于筛选主查询中的数据,保留满足条件的行。具体来说,主查询会查找 `called_number` 列中的值在子查询中出现过的行。
总的来说,这段 SQL 的作用是筛选出在过去两小时内被不少于 5 个不同的用户拨打过的号码。
相关问题
SELECT caller_number, called_number FROM ( SELECT caller_number, called_number, call_start_time, IF(called_number=@prev_called_number, @cnt:=@cnt+1, @cnt:=1) AS cnt, @prev_called_number:=called_number FROM call_records, (SELECT @prev_called_number:=NULL, @cnt:=1) AS vars WHERE call_start_time >= DATE_SUB(NOW(), INTERVAL 2 HOUR) AND caller_number NOT LIKE '0%' ORDER BY called_number, call_start_time ) AS t WHERE cnt >= 5
这是一个MySQL查询语句,它的作用是查询当前时间到前两小时的话单数据,然后统计同一个被叫号码总共被拨打的次数,如果超过5次,则认为异常,最后返回拨打号码和被叫号码。
具体的查询逻辑如下:
1. 查询话单表中,通话开始时间在当前时间到前两小时之间的记录。
```sql
WHERE call_start_time >= DATE_SUB(NOW(), INTERVAL 2 HOUR)
```
2. 排除掉拨打号码以0开头的记录。
```sql
AND caller_number NOT LIKE '0%'
```
3. 对查询结果按照被叫号码和通话开始时间进行排序,并使用MySQL的变量和IF函数,统计每个被叫号码被拨打的次数。
```sql
SELECT caller_number, called_number, call_start_time,
IF(called_number=@prev_called_number, @cnt:=@cnt+1, @cnt:=1) AS cnt,
@prev_called_number:=called_number
FROM call_records, (SELECT @prev_called_number:=NULL, @cnt:=1) AS vars
WHERE call_start_time >= DATE_SUB(NOW(), INTERVAL 2 HOUR)
AND caller_number NOT LIKE '0%'
ORDER BY called_number, call_start_time
```
4. 最后将统计结果作为子查询,筛选出被拨打次数超过5次的记录,并返回拨打号码和被叫号码。
```sql
SELECT caller_number, called_number
FROM (
SELECT caller_number, called_number, call_start_time,
IF(called_number=@prev_called_number, @cnt:=@cnt+1, @cnt:=1) AS cnt,
@prev_called_number:=called_number
FROM call_records, (SELECT @prev_called_number:=NULL, @cnt:=1) AS vars
WHERE call_start_time >= DATE_SUB(NOW(), INTERVAL 2 HOUR)
AND caller_number NOT LIKE '0%'
ORDER BY called_number, call_start_time
) AS t
WHERE cnt >= 5
```
注意:这个SQL查询语句只实现了被拨打次数超过5次的监控规则,还需要结合其他查询和处理,才能实现完整的异常监控。
caller_number NOT LIKE '0%' AND LENGTH(caller_number) > 5 AND LENGTH(caller_number) < 16 AND LENGTH(called_number) > 5 AND LENGTH(called_number) < 16 AND (SELECT COUNT(*) FROM call_records WHERE caller_number=cr.caller_number AND called_number=cr.called_number AND call_start_time >= DATE_SUB(NOW(), INTERVAL 2 HOUR)) >= 10分析这段代码
这段代码是一个SQL语句的查询条件,其中包含了多个限制条件:
1. caller_number不以0开头;
2. caller_number和called_number的长度在6到15之间;
3. 查询与当前时间相差两小时以内的通话记录;
4. 同一个caller_number和called_number对应的通话记录数量要大于等于10。
这段代码的目的是查询满足上述限制条件的通话记录。其中第4个条件可以用于过滤出经常通话的号码。
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