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4. Two tables A and B are given: A B X Y 1 1 2 2 3 5 7 How many rows will be in the result set of the following query? SELECT A.X, B.Y FROM A, B WHERE A.X < 3 AND B.Y > = 2 5 Rows 6 Rows 7 Rows 10 Rows 12 Rows
No doubt, by now, you have run the query to see what the actual row count is. This looks like an exam question, so I don't want to come right out and give the answer. Let's see if this gets us close... In order to calculate it without running the query, you need to apply your filters to each set (table), A and B, then multiply the rows in the filtered sets. First look at each set independently. Looking at the filter `A.X < 3`, how many rows will be in filtered set A? How many rows will be in filtered set B if `B.Y > = 2`? The number of rows in the result set will be the product of the rows in the filtered sets: `Filtered Set A * Filtered Set B`
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