Archive for November 25th, 2009
MySQL: Selecting records holding group-wise maximum (resolving ties)
Continuing the series on selecting records holding group-wise maximums.
The approach shown in the previous article is quite efficient, however, it can only be relied upon if the column being maximized is unique.
If the column is not unique (even along with the grouping column), the ties are possible: multiple records can satisfy the condition of holding a group-wise maximum
.
In this article, I'll show how to resolve the ties.
Let's recreate the table we used in the previous article:
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