A subquery example
We happened recently to solve a problem of this type: we had a structure in which, for each category (shown in a table A) had a number of items of detail (in a table B) numeric values (the latter given in a table C that implemented them a one to many relationship between A and B). We were required to get the maximum value for each category and detail which he was associated. The following example is inspired from the problem that we faced. For obvious reasons, the logic was applied to the sample tables are different from the real...