SQL查询以识别重复项对

Question

I'm trying to write a query which will pair up impressions and conversions from the same IP address in my database. I have a table of impressions and their IP addresses, and an impression can be of the type 'view' or 'conversion' (defined in the column 'name').

So basically, I need to identify groups of records with the same IP address, which contain both a view and a conversion.

After an hour of Googling I've got as far as the below, which isn't very far but should give an idea of the objects involved:

SELECT ip_address, name, COUNT(1) as CNT 
FROM Impressions
GROUP BY ip_address, name;

Can anyone advise on the best way to do this?

Answer 1

You need to use the HAVING clause with a conditional count. You also need to remove name from the GROUP BY as this will treat your two different types separately.

SELECT  ip_address, 
        COUNT(CASE WHEN Name = 'View' THEN 1 END) AS Views,
        COUNT(CASE WHEN Name = 'Conversion' THEN 1 END) AS Conversions,
        COUNT(1) as CNT 
FROM    Impressions
GROUP BY ip_address
HAVING  COUNT(CASE WHEN Name = 'View' THEN 1 END) > 0
AND     COUNT(CASE WHEN Name = 'Conversion' THEN 1 END) > 0;

Answer 2

You can try this:

SELECT 
  i.ip_address AS ip, 
  GROUP_CONCAT(DISTINCT CAST(i.name AS CHAR)) AS nameList,
  SUM(IF(i.name = 'View', 1, 0)) AS viewCount, 
  SUM(IF(i.name = 'Conversion', 1, 0)) AS conversionCount
FROM Impressions i
GROUP BY i.ip_address;

You will get a comma delimited list of names containing both 'view' & 'conversion' and their separate counts.

Answer 3

Please try...

SELECT ip_address, name, COUNT(1) cnt as CNT FROM Impressions GROUP BY name,IP_address Having count(IP_address) > 1;