Using Having to subquery : Introduction « Subquery « MySQL Tutorial






  1. MySQL Tutorial
  2. Subquery
  3. Introduction
mysql>
mysql> CREATE TABLE Books(
    ->    BookID SMALLINT NOT NULL PRIMARY KEY,
    ->    BookTitle VARCHAR(60) NOT NULL,
    ->    Copyright YEAR NOT NULL
    -> )
    -> ENGINE=INNODB;
Query OK, 0 rows affected (0.05 sec)

mysql>
mysql>
mysql> INSERT INTO Books VALUES (12786, 'Java',           1934),
    ->                          (13331, 'MySQL',          1919),
    ->                          (14356, 'PHP',            1966),
    ->                          (15729, 'PERL',           1932),
    ->                          (16284, 'Oracle',         1996),
    ->                          (17695, 'Pl/SQL',         1980),
    ->                          (19264, 'JavaScript',     1992),
    ->                          (19354, 'www.java2s.com', 1993);
Query OK, 8 rows affected (0.02 sec)
Records: 8  Duplicates: 0  Warnings: 0

mysql>
mysql>
mysql> CREATE TABLE Authors(
    ->    AuthID SMALLINT NOT NULL PRIMARY KEY,
    ->    AuthFN VARCHAR(20),
    ->    AuthMN VARCHAR(20),
    ->    AuthLN VARCHAR(20)
    -> )
    -> ENGINE=INNODB;
Query OK, 0 rows affected (0.05 sec)

mysql>
mysql>
mysql> INSERT INTO Authors VALUES (1006, 'H', 'S.', 'T'),
    ->                            (1007, 'J', 'C',  'O'),
    ->                            (1008, 'B', NULL, 'E'),
    ->                            (1009, 'R', 'M',  'R'),
    ->                            (1010, 'J', 'K',  'T'),
    ->                            (1011, 'J', 'G.', 'N'),
    ->                            (1012, 'A', NULL, 'P'),
    ->                            (1013, 'A', NULL, 'W'),
    ->                            (1014, 'N', NULL, 'A');
Query OK, 9 rows affected (0.05 sec)
Records: 9  Duplicates: 0  Warnings: 0

mysql>
mysql>
mysql> CREATE TABLE AuthorBook(
    ->    AuthID SMALLINT NOT NULL,
    ->    BookID SMALLINT NOT NULL,
    ->    PRIMARY KEY (AuthID, BookID),
    ->    FOREIGN KEY (AuthID) REFERENCES Authors (AuthID),
    ->    FOREIGN KEY (BookID) REFERENCES Books (BookID)
    -> )
    -> ENGINE=INNODB;
Query OK, 0 rows affected (0.05 sec)

mysql>
mysql>
mysql> INSERT INTO AuthorBook VALUES (1006, 14356),
    ->                               (1008, 15729),
    ->                               (1009, 12786),
    ->                               (1010, 17695),
    ->                               (1011, 15729),
    ->                               (1012, 19264),
    ->                               (1012, 19354),
    ->                               (1014, 16284);
Query OK, 8 rows affected (0.01 sec)
Records: 8  Duplicates: 0  Warnings: 0

mysql>
mysql>
mysql> select * from Authors;
+--------+--------+--------+--------+
| AuthID | AuthFN | AuthMN | AuthLN |
+--------+--------+--------+--------+
|   1006 | H      | S.     | T      |
|   1007 | J      | C      | O      |
|   1008 | B      | NULL   | E      |
|   1009 | R      | M      | R      |
|   1010 | J      | K      | T      |
|   1011 | J      | G.     | N      |
|   1012 | A      | NULL   | P      |
|   1013 | A      | NULL   | W      |
|   1014 | N      | NULL   | A      |
+--------+--------+--------+--------+
9 rows in set (0.00 sec)

mysql> select * from Books;
+--------+----------------+-----------+
| BookID | BookTitle      | Copyright |
+--------+----------------+-----------+
|  12786 | Java           |      1934 |
|  13331 | MySQL          |      1919 |
|  14356 | PHP            |      1966 |
|  15729 | PERL           |      1932 |
|  16284 | Oracle         |      1996 |
|  17695 | Pl/SQL         |      1980 |
|  19264 | JavaScript     |      1992 |
|  19354 | www.java2s.com |      1993 |
+--------+----------------+-----------+
8 rows in set (0.00 sec)

mysql> select * from AuthorBook;
+--------+--------+
| AuthID | BookID |
+--------+--------+
|   1009 |  12786 |
|   1006 |  14356 |
|   1008 |  15729 |
|   1011 |  15729 |
|   1014 |  16284 |
|   1010 |  17695 |
|   1012 |  19264 |
|   1012 |  19354 |
+--------+--------+
8 rows in set (0.00 sec)

mysql>
mysql>
mysql> SELECT BookID FROM AuthorBook WHERE AuthID IN
    ->    (
    ->       SELECT AuthID FROM AuthorBook
    ->       GROUP BY AuthID
    ->       HAVING COUNT(*)>1
    ->    );
+--------+
| BookID |
+--------+
|  19264 |
|  19354 |
+--------+
2 rows in set (0.00 sec)

mysql>
mysql>
mysql> drop table AuthorBook;
Query OK, 0 rows affected (0.05 sec)

mysql> drop table Books;
Query OK, 0 rows affected (0.03 sec)

mysql> drop table Authors;
Query OK, 0 rows affected (0.05 sec)








6.1.Introduction
6.1.1.A subquery is a SELECT statement within another statement.
6.1.2.Using Join in the subquery
6.1.3.Using the aggregate function in subquery
6.1.4.Update with subquery
6.1.5.Using Having to subquery
6.1.6.Delete with subquery
6.1.7.Get the Row Holding the Maximum of a Certain Column with sub query in where clause
6.1.8.The Rows Holding the Group-wise Maximum of a Certain Field
6.1.9.Comparisons Using Subqueries
6.1.10.Find all rows in a table containing a value that occurs twice in a given column
6.1.11.Subqueries in the FROM clause
6.1.12.NULL Subquery with gradter than (>)
6.1.13.A scalar subquery can be part of an expression
6.1.14.The Subquery as Scalar Operand