如何从多个表中选择相同的列

Question

I have 2 tables as follows, with the same columns

Table 1
Name             Subject
Alan Smith       Biology
Fred Jones       Biology
Anne Pool        Chemistry


Table 2
Name             Subject
Paul Jones       Chemistry 
Ted Williams     Biology

Question: What SELECT statement will retrieve just rows where Subject is Biology from the 2 tables?

Answer 1

SELECT Name 
FROM table2 
WHERE Subject='Biology' 
    UNION SELECT Name 
    FROM table1 
    WHERE Subject='Biology'

UNION combines the result sets from multiple SELECT statements, while using it, the columns in both tables have to be the same.

Answer 2

在每个表上执行两个SELECT * FROM myTable WHERE subject = 'biology'查询并处理该数据。