Question: Divide-and-Conquer for Multi-Unit Queries Query Condition To decide whether a given query requirement is single-unit or multi-unit, we need to find its query condition first.
Divide-and-Conquer for Multi-Unit Queries
Query Condition
To decide whether a given query requirement is single-unit or multi-unit, we need to find its query condition first. Query condition is the part of the query requirement that specifies what rows should be kept in the query result. In English grammar, this is often the adjective clause of a sentence. For example, if the query requirement is to find the names of the programs that are offered by departments whose IDs are CS and EE, then the query condition is the underlined part of the sentence.
Note that when a query requirement does not have a query condition, it is a single-unit query.
Query: Find all faculty members who work for the department with ID 'CS'.
Does the query have a query condition? If yes, what is the query condition?
Answer:
Query: Find names and GPAs of all students.
Does the query have a query condition? If yes, what is the query condition?
Answer:
Query: For students majoring in the program with ID 'P000', return their names and GPAs.
Does the query have a query condition? If yes, what is the query condition?
Answer:
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