Python中實現count(distinct )

假設一個表有6個字段c1,c2,c3,c4,c5,c6，有如下的sql語句:

select c1,count(distinct(c6)) from tbl where c3>1 group by c3;

Python中asq模塊可以實現類似的查詢，以下用一個示例說明。

 

#!/usr/bin/env python2.7  
#-*- encoding: utf-8 -*-  
  
import os  
from datetime import *  
import time  
from asq.initiators import query  
  
def test1():  
        src_list = [[6,6,6,3,7,9],[3,1,1,45,6,34],[2,9,5,435,56,34],[8,6,8,23,4,32],[2,6,8,435,2,8],[1,3,6,432,5,22],[1,3,5,6,2,435],[2,4,6,34,2,12]]  
  
        res_list = query(src_list).where(lambda p: p[2]>1).group_by(lambda p:p[2]).select(lambda p:[p[0][0],p.distinct(lambda p: p[5]).count()]).to_list()  
  
        print res_list  
  
if __name__ == '__main__':  
  
     test1()  

 

 

 

 

運行結果:

 

[[6, 3], [2, 2], [8, 2]]
[Finished in 0.1s]

 

asq函數的邏輯順序依次是: where-->group by --> select --> distinct -->返回結果列表。