Besonderhede van voorbeeld: -7403032996342038929

English

SELECT e.ID, e.LastName, e.FirstName, pn.Number FROM Employee e LEFT OUTER JOIN PhoneNumber pn ON e.ID = pn.ID; The result set generated by this query demonstrates how SQL uses Null as a placeholder for values missing from the right-hand (PhoneNumber) table, as shown below.

Chinese

SELECT e.ID, e.LastName, e.FirstName, pn.Number FROM Employee e LEFT OUTER JOIN PhoneNumber pn ON e.ID = pn.ID; 此查詢生成的結果集演示 SQL如何使用 Null作為右側(PhoneNumber)表中缺少的值的佔位符,如下所示。