MySQLで複数のAND条件を機能させる方法は？

MySQLで複数のAND条件を操作するには、次の構文を使用します-

select *from yourTableName where yourColumnName1=yourValue1 and yourColumnName2=yourValue2 and yourColumnName3=yourValue3;

まずテーブルを作成しましょう-

mysql> create table DemoTable
   (
   StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY,
   StudentName varchar(20),
   StudentAge int,
   StudentCountryName varchar(40)
   );
Query OK, 0 rows affected (0.59 sec)

挿入コマンド-

mysql> insert into DemoTable(StudentName,StudentAge,StudentCountryName) values('John',23,'US');
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable(StudentName,StudentAge,StudentCountryName) values('Carol',21,'UK');
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable(StudentName,StudentAge,StudentCountryName) values('John',21,'US');
Query OK, 1 row affected (0.12 sec)
mysql> insert into DemoTable(StudentName,StudentAge,StudentCountryName) values('John',21,'AUS');
Query OK, 1 row affected (0.14 sec)

selectステートメントを使用してテーブルのすべてのレコードを表示する-

mysql> select *from DemoTable;

出力

+-----------+-------------+------------+--------------------+
| StudentId | StudentName | StudentAge | StudentCountryName |
+-----------+-------------+------------+--------------------+
| 1         | John        | 23         | US                 |
| 2         | Carol       | 21         | UK                 |
| 3         | John        | 21         | US                 |
| 4         | John        | 21         | AUS                |
+-----------+-------------+------------+--------------------+
4 rows in set (0.00 sec)

以下は、MySQLの複数のAND条件のクエリです-

mysql> select *from DemoTable where StudentName="John" and StudentAge=21 and StudentCountryName="AUS";

出力

+-----------+-------------+------------+--------------------+
| StudentId | StudentName | StudentAge | StudentCountryName |
+-----------+-------------+------------+--------------------+
| 4         | John        | 21         | AUS                |
+-----------+-------------+------------+--------------------+
1 row in set (0.00 sec)