SQL/MySQL/Join/Join Delete
Delete command: JOIN two tables
<source lang="sql">
/* mysql> select * from Authors; +--------+-----------------+------------------+----------------+ | AuthID | AuthorFirstName | AuthorMiddleName | AuthorLastName | +--------+-----------------+------------------+----------------+ | 1006 | Henry | S. | Thompson | | 1007 | Jason | Carol | Oak | | 1008 | James | NULL | Elk | | 1009 | Tom | M | Ride | | 1010 | Jack | K | Ken | | 1011 | Mary | G. | Lee | | 1012 | Annie | NULL | Watts | | 1013 | Alan | NULL | Wang | | 1014 | Nelson | NULL | Yin | +--------+-----------------+------------------+----------------+ 9 rows in set (0.02 sec) mysql> DELETE ab
-> FROM AuthorArticle AS ab, Authors AS a -> WHERE ab.AuthID=a.AuthID AND AuthorLastName="Watts";
Query OK, 2 rows affected (0.05 sec) mysql> select * from Authors; +--------+-----------------+------------------+----------------+ | AuthID | AuthorFirstName | AuthorMiddleName | AuthorLastName | +--------+-----------------+------------------+----------------+ | 1006 | Henry | S. | Thompson | | 1007 | Jason | Carol | Oak | | 1008 | James | NULL | Elk | | 1009 | Tom | M | Ride | | 1010 | Jack | K | Ken | | 1011 | Mary | G. | Lee | | 1012 | Annie | NULL | Watts | | 1013 | Alan | NULL | Wang | | 1014 | Nelson | NULL | Yin | +--------+-----------------+------------------+----------------+ 9 rows in set (0.01 sec)
- /
Drop table Articles; Drop table Authors; Drop table AuthorArticle;
CREATE TABLE Articles (
ArticleID SMALLINT NOT NULL PRIMARY KEY, ArticleTitle VARCHAR(60) NOT NULL, Copyright YEAR NOT NULL
) ENGINE=INNODB;
INSERT INTO Articles VALUES (12786, "How write a paper", 1934),
(13331, "Publish a paper", 1919),
(14356, "Sell a paper", 1966),
(15729, "Buy a paper", 1932),
(16284, "Conferences", 1996),
(17695, "Journal", 1980),
(19264, "Information", 1992),
(19354, "AI", 1993);
CREATE TABLE Authors (
AuthID SMALLINT NOT NULL PRIMARY KEY, AuthorFirstName VARCHAR(20), AuthorMiddleName VARCHAR(20), AuthorLastName VARCHAR(20)
) ENGINE=INNODB;
INSERT INTO Authors VALUES (1006, "Henry", "S.", "Thompson"),
(1007, "Jason", "Carol", "Oak"),
(1008, "James", NULL, "Elk"),
(1009, "Tom", "M", "Ride"),
(1010, "Jack", "K", "Ken"),
(1011, "Mary", "G.", "Lee"),
(1012, "Annie", NULL, "Peng"),
(1013, "Alan", NULL, "Wang"),
(1014, "Nelson", NULL, "Yin");
CREATE TABLE AuthorArticle (
AuthID SMALLINT NOT NULL, ArticleID SMALLINT NOT NULL, PRIMARY KEY (AuthID, ArticleID), FOREIGN KEY (AuthID) REFERENCES Authors (AuthID), FOREIGN KEY (ArticleID) REFERENCES Articles (ArticleID)
) ENGINE=INNODB;
INSERT INTO AuthorArticle VALUES (1006, 14356),
(1008, 15729),
(1009, 12786),
(1010, 17695),
(1011, 15729),
(1012, 19264),
(1012, 19354),
(1014, 16284);
select * from Authors;
DELETE ab FROM AuthorArticle AS ab, Authors AS a WHERE ab.AuthID=a.AuthID AND AuthorLastName="Watts"; select * from Authors;
</source>
Delete records from two tables using JOIN
<source lang="sql">
/* mysql> select * from Authors; +--------+-----------------+------------------+----------------+ | AuthID | AuthorFirstName | AuthorMiddleName | AuthorLastName | +--------+-----------------+------------------+----------------+ | 1006 | Henry | S. | Thompson | | 1007 | Jason | Carol | Oak | | 1008 | James | NULL | Elk | | 1009 | Tom | M | Ride | | 1010 | Jack | K | Ken | | 1011 | Mary | G. | Lee | | 1012 | Annie | NULL | Watts | | 1013 | Alan | NULL | Wang | | 1014 | Nelson | NULL | Yin | +--------+-----------------+------------------+----------------+ 9 rows in set (0.01 sec) mysql> DELETE ab, b
-> FROM Authors AS a, AuthorArticle AS ab, Articles AS b -> WHERE a.AuthID=ab.AuthID AND ab.ArticleID=b.ArticleID -> AND AuthorLastName="Henry";
Query OK, 0 rows affected (0.00 sec) mysql> select * from Authors; +--------+-----------------+------------------+----------------+ | AuthID | AuthorFirstName | AuthorMiddleName | AuthorLastName | +--------+-----------------+------------------+----------------+ | 1006 | Henry | S. | Thompson | | 1007 | Jason | Carol | Oak | | 1008 | James | NULL | Elk | | 1009 | Tom | M | Ride | | 1010 | Jack | K | Ken | | 1011 | Mary | G. | Lee | | 1012 | Annie | NULL | Watts | | 1013 | Alan | NULL | Wang | | 1014 | Nelson | NULL | Yin | +--------+-----------------+------------------+----------------+ 9 rows in set (0.00 sec)
- /
Drop table Articles; Drop table Authors; Drop table AuthorArticle;
CREATE TABLE Articles (
ArticleID SMALLINT NOT NULL PRIMARY KEY, ArticleTitle VARCHAR(60) NOT NULL, Copyright YEAR NOT NULL
) ENGINE=INNODB;
INSERT INTO Articles VALUES (12786, "How write a paper", 1934),
(13331, "Publish a paper", 1919),
(14356, "Sell a paper", 1966),
(15729, "Buy a paper", 1932),
(16284, "Conferences", 1996),
(17695, "Journal", 1980),
(19264, "Information", 1992),
(19354, "AI", 1993);
CREATE TABLE Authors (
AuthID SMALLINT NOT NULL PRIMARY KEY, AuthorFirstName VARCHAR(20), AuthorMiddleName VARCHAR(20), AuthorLastName VARCHAR(20)
) ENGINE=INNODB;
INSERT INTO Authors VALUES (1006, "Henry", "S.", "Thompson"),
(1007, "Jason", "Carol", "Oak"),
(1008, "James", NULL, "Elk"),
(1009, "Tom", "M", "Ride"),
(1010, "Jack", "K", "Ken"),
(1011, "Mary", "G.", "Lee"),
(1012, "Annie", NULL, "Peng"),
(1013, "Alan", NULL, "Wang"),
(1014, "Nelson", NULL, "Yin");
CREATE TABLE AuthorArticle (
AuthID SMALLINT NOT NULL, ArticleID SMALLINT NOT NULL, PRIMARY KEY (AuthID, ArticleID), FOREIGN KEY (AuthID) REFERENCES Authors (AuthID), FOREIGN KEY (ArticleID) REFERENCES Articles (ArticleID)
) ENGINE=INNODB;
INSERT INTO AuthorArticle VALUES (1006, 14356),
(1008, 15729),
(1009, 12786),
(1010, 17695),
(1011, 15729),
(1012, 19264),
(1012, 19354),
(1014, 16284);
select * from Authors; DELETE ab, b FROM Authors AS a, AuthorArticle AS ab, Articles AS b WHERE a.AuthID=ab.AuthID AND ab.ArticleID=b.ArticleID
AND AuthorLastName="Henry";
select * from Authors;
</source>
Delete with INNER JOIN
<source lang="sql">
/* mysql> Select * from Authors; +--------+-----------------+------------------+----------------+ | AuthID | AuthorFirstName | AuthorMiddleName | AuthorLastName | +--------+-----------------+------------------+----------------+ | 1006 | Henry | S. | Thompson | | 1007 | Jason | Carol | Oak | | 1008 | James | NULL | Elk | | 1009 | Tom | M | Ride | | 1010 | Jack | K | Ken | | 1011 | Mary | G. | Lee | | 1012 | Annie | NULL | Watts | | 1013 | Alan | NULL | Wang | | 1014 | Nelson | NULL | Yin | +--------+-----------------+------------------+----------------+ 9 rows in set (0.01 sec) mysql> DELETE ab, b
-> FROM Authors AS a INNER JOIN AuthorArticle AS ab ON a.AuthID=ab.AuthID -> INNER JOIN Articles AS b ON ab.ArticleID=b.ArticleID -> WHERE AuthorLastName="Tom";
Query OK, 0 rows affected (0.01 sec) mysql> Select * from Authors; +--------+-----------------+------------------+----------------+ | AuthID | AuthorFirstName | AuthorMiddleName | AuthorLastName | +--------+-----------------+------------------+----------------+ | 1006 | Henry | S. | Thompson | | 1007 | Jason | Carol | Oak | | 1008 | James | NULL | Elk | | 1009 | Tom | M | Ride | | 1010 | Jack | K | Ken | | 1011 | Mary | G. | Lee | | 1012 | Annie | NULL | Watts | | 1013 | Alan | NULL | Wang | | 1014 | Nelson | NULL | Yin | +--------+-----------------+------------------+----------------+ 9 rows in set (0.00 sec)
- /
Drop table Articles; Drop table Authors; Drop table AuthorArticle;
CREATE TABLE Articles (
ArticleID SMALLINT NOT NULL PRIMARY KEY, ArticleTitle VARCHAR(60) NOT NULL, Copyright YEAR NOT NULL
) ENGINE=INNODB;
INSERT INTO Articles VALUES (12786, "How write a paper", 1934),
(13331, "Publish a paper", 1919),
(14356, "Sell a paper", 1966),
(15729, "Buy a paper", 1932),
(16284, "Conferences", 1996),
(17695, "Journal", 1980),
(19264, "Information", 1992),
(19354, "AI", 1993);
CREATE TABLE Authors (
AuthID SMALLINT NOT NULL PRIMARY KEY, AuthorFirstName VARCHAR(20), AuthorMiddleName VARCHAR(20), AuthorLastName VARCHAR(20)
) ENGINE=INNODB;
INSERT INTO Authors VALUES (1006, "Henry", "S.", "Thompson"),
(1007, "Jason", "Carol", "Oak"),
(1008, "James", NULL, "Elk"),
(1009, "Tom", "M", "Ride"),
(1010, "Jack", "K", "Ken"),
(1011, "Mary", "G.", "Lee"),
(1012, "Annie", NULL, "Peng"),
(1013, "Alan", NULL, "Wang"),
(1014, "Nelson", NULL, "Yin");
CREATE TABLE AuthorArticle (
AuthID SMALLINT NOT NULL, ArticleID SMALLINT NOT NULL, PRIMARY KEY (AuthID, ArticleID), FOREIGN KEY (AuthID) REFERENCES Authors (AuthID), FOREIGN KEY (ArticleID) REFERENCES Articles (ArticleID)
) ENGINE=INNODB;
INSERT INTO AuthorArticle VALUES (1006, 14356),
(1008, 15729),
(1009, 12786),
(1010, 17695),
(1011, 15729),
(1012, 19264),
(1012, 19354),
(1014, 16284);
Select * from Authors;
DELETE ab, b FROM Authors AS a INNER JOIN AuthorArticle AS ab ON a.AuthID=ab.AuthID
INNER JOIN Articles AS b ON ab.ArticleID=b.ArticleID
WHERE AuthorLastName="Tom"; Select * from Authors;
</source>
