I need to write a query that selects a minimum value and it\'s second most minimum value from a list of integers.
Grabbing the smallest value is obvious:
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Use an analytic function
SELECT value
FROM (SELECT value,
dense_rank() over (order by value asc) rnk
FROM table)
WHERE rnk = 2
The analytic functions RANK, DENSE_RANK, and ROW_NUMBER are identical except for how they handle ties. RANK uses a sports-style process of breaking ties so if two rows tie for a rank of 1, the next row has a rank of 3. DENSE_RANK gives both of the rows tied for first place a rank of 1 and then assigns the next row a rank of 2. ROW_NUMBER arbitrarily breaks the tie and gives one of the two rows with the lowest value a rank of 1 and the other a rank of 2.