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Get the minimum value between two columns for each row

This is my datasheet:

| uid |   date   | visit | transactionDate |
+-----+----------+-------+-----------------+
|  1  | 6/2/2014 |   1   |     6/9/2014    |
|  1  | 6/2/2014 |   1   |     8/4/2014    |
|  2  | 6/2/2014 |   1   |     8/2/2014    |
|  2  | 6/2/2014 |   1   |     10/17/2014  |
|  2  | 6/2/2014 |   1   |     10/20/2014  |
|  3  | 6/2/2014 |   1   |     6/9/2014    |
|  3  | 6/2/2014 |   1   |     6/10/2014   |
|  3  | 6/2/2014 |   1   |     6/11/2014   | 
|  3  | 6/2/2014 |   1   |     6/12/2014   |
|  3  | 6/2/2014 |   1   |     6/14/2014   |
|  3  | 6/2/2014 |   1   |     6/15/2014   |
|  3  | 6/2/2014 |   1   |     6/17/2014   |
|  3  | 6/2/2014 |   1   |     6/18/2014   |
|  3  | 6/2/2014 |   1   |     6/23/2014   |

I am trying to write a query to pull at least two date and date columns of a transaction. Is there a way to do something like MIN (date, transactionDate)? The request should select something like this:

uid 1 then minimum of date and transaction_dt
uid 2 then min date and transaction_dt
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4 answers


Use a CASE

condition.



SELECT uid, visit, 
   CASE WHEN date < transactionDate THEN date ELSE transactionDate END AS minDate
FROM table;
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   SELECT UID ,MIN(tdate) FROM 
       (SELECT a.uid, a.date tdate FROM tableA a 
      UNION 
      SELECT a.uid, a.transaction_dt tdate FROM tableA a ) AS tABLE2 T GROUP BY T.UID


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If you're looking for the minimum for each line:

select uid,visit,least(date,transactionDate) as minDate from t;

If you are looking for the minimum group for uid:

select uid,sum(visit) as totalVisits,min(least(date,transactionDate)) as minDate
  from t
  group by uid;
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Use LEAST () with the MIN () function .

Try the following:

SELECT a.uid, MIN(LEAST(a.date, a.transaction_dt)) tdate 
FROM tableA a 
GROUP BY a.uid;

OR

SELECT a.uid, MIN(a.tdate) tdate
FROM (SELECT a.uid, MIN(a.date) tdate FROM tableA a GROUP BY a.uid
      UNION 
      SELECT a.uid, MIN(a.transaction_dt) tdate FROM tableA a GROUP BY a.uid
     ) AS a
GROUP BY a.uid;
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