Recent questions tagged nested-query-with-correlation

Commodity items have some positive or negative changes in theirprices each week. Each trading company picks a portfolio of com-modity items, that is, they have one or mor...

Consider the following instances $R.$A1234BNull122The number of tuples returned by the following $\text{SQL query}$ is$?$$>$select $*$ from $R$ as $R_{1}$ where not exist...