Question

我在postgres数据库中有一个列，它记录了我们网站上页面的搜索查询字符串。

该列包含

等数据

"a=2&b=4"
"a=2,3"
"b=4&a=3"
"a=4&a=3"

我想计算某个参数（a）的每个值的频率。

value | freq
------|------
3     | 3
2     | 2
4     | 1

无论如何要在单个SQL语句中执行此操作？

Answer 1

这样的事情：

def enrich(xRDD: RDD[xObject], yRDD: RDD[yObject], zRDD: RDD[zObject]): RDD[Result] = {
     functionB(functionA(xRDD, yRDD), zRDD)
}

在线示例：http://rextester.com/OXM67442

Answer 2

尝试这样的事情：

select data_value,count(*) from (
  select data_name,unnest(string_to_array(data_values,',')) data_value from (
    select split_part(data_array,'=',1) data_name ,split_part(data_array,'=',2) data_values from (
          select unnest(string_to_array(mydata,'&')) data_array from mytable
         ) a
       ) b
    ) c where data_name='a' group by 1 order by 1

Answer 3

假设保留计数的表名为paramcount：

WITH vals(v) AS
   (SELECT regexp_replace(p, '^.*=', '')
    FROM regexp_split_to_table(
            'b=4&a=3,2',
            '&|,'
         ) p(p)
   )
INSERT INTO paramcount (value, freq)
   SELECT v, 1 FROM vals
ON CONFLICT (value)
   DO UPDATE SET freq = paramcount.freq + 1
      WHERE paramcount.value = EXCLUDED.value;

Answer 4

在＆＃39; a =＆＃39;
将其拆分为数字

统计值

select v, count(*) from (
   SELECT c,unnest(string_to_array(unnest(regexp_matches(c,'a=([0-9,]+)','g')),',')) as v FROM qrs
) x group by v;

参数多态：

WITH argname(aname) as (values ('a'::TEXT))
select v, count(*) from (SELECT c,unnest(string_to_array(unnest(regexp_matches(c,aname||'=([0-9,]+)','g')),',')) as v FROM qrs,argname) x group by v;

如何计算postgres中一组查询字符串中整数的频率

4 个答案: