UNIONを使用して複数のテーブルから選択する

クエリを更新していただきありがとうございます。これで、WHERE条件が最後のにのみ適用されることがわかります。 UNIONedクエリ。 どちらかにする必要があります そのWHERE句を各クエリに追加するか、副選択としてラップしてWHERE句を適用します。

select s.id as id, s.email as email, s.password as password, s.role as role from tblStudents s
where email = "[email protected]"
union
select a.id as id, a.email as email, a.password as password, a.role as role from tblAdmin a
where email = "[email protected]"
union
select t.id as id, t.email as email, t.password as password, t.role as role from tblTeachers t
where email = "[email protected]"

または

SELECT * FROM (
select s.id as id, s.email as email, s.password as password, s.role as role from tblStudents s
union
select a.id as id, a.email as email, a.password as password, a.role as role from tblAdmin a
union
select t.id as id, t.email as email, t.password as password, t.role as role from tblTeachers t
) foo where email = "[email protected]"