You have two data sets. One data set contains customer name and age information along with a customer ID. The second data set contains the customer ID along with address information. There are no…

Question

Options

• AInner join
• BOuter join
• CPartial outer join
• DAnti-join

• A
  6% (1)
• B
  11% (2)
• C
  83% (15)

Explanation

A partial outer join (left outer join) returns all records from the customer table regardless of whether a matching address exists - customers without an address appear with NULL values in the address fields, making them visible in the result set. An inner join (A) only returns rows where a match exists in both tables, so customers without addresses are excluded entirely. A full outer join (B) returns all rows from both tables including unmatched rows from the address side, but since the problem states all addresses belong to a customer, this adds no value and doesn't specifically isolate address-less customers. An anti-join (D) returns only the customers with no match in the address table - it's the inverse of an inner join and would actually be too restrictive here, omitting customers who do have addresses.

Memory tip: Think "partial" = one side is preserved completely. The customer table is the "dominant" side, so all customers survive the join - even the ones standing alone without an address partner.

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