Select multiple columns with only one distinct column in sql

Question

I need to query an SQL database to find all distinct values of one column and I need an arbitrary value from another two columns. For example, consider the following table with three columns: CurrencyCode, BuyRate and SellRate:

CurrencyCode  BuyRate  SellRate
AUD           1.037    1.97
AUD           1.079    1.99
EUR           0.7288   0.8763
EUR           0.731    0.88
GBP           0.59     0.72

I wish to retrieve one row with distinct CurrencyCode, perhaps getting these three rows:

CurrencyCode  BuyRate  SellRate
AUD           1.037    1.97
EUR           0.7288   0.8763
GBP           0.59     0.72

I tried my SQL query like:

SELECT distinct CurrencyCode, BuyRate, SellRate FROM  Currencies

But I am not getting the desired result as it districts all the columns.

Answer 1

Try with GROUP BY clause and MIN function as below

SELECT CurrencyCode, MIN(BuyRate), MIN(SellRate)
FROM  Currencies
GROUP BY CurrencyCode