How do Corelated Sub queries work? How do we identify and distinguish them from a normal sub query and how frequently are corelated sub queries used in practical applications. Am new to teradata and it would be great if someone could walk me through the 'Corelated Sub query' concept with some simple explanatory codes. Thanks .
In co related subquery the subquery references an attribute of the parent(base query) hence cannot be executed prior to the base query. For every row in the base query the subquery is executed unlike simple subquery where ... the subquery is executed first ,and based on the answer provided by the suquery the base query is executed.