Sub query with string concatenate : Sub query « Select Clause « SQL / MySQL






  1. SQL / MySQL
  2. Select Clause
  3. Sub query

Sub query with string concatenate

   
/*

mysql> SELECT CONCAT_WS(' ', AuthorFirstName, AuthorMiddleName, AuthorLastName)
AS Author
    -> FROM Authors
    -> WHERE AuthID=
    ->    (
    ->       SELECT ab.AuthID
    ->       FROM AuthorArticle AS ab, Articles AS b
    ->       WHERE ab.ArticleID=b.ArticleID AND ArticleTitle='AI'
    ->    );
+-------------+
| Author      |
+-------------+
| Annie Watts |
+-------------+
1 row 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 CONCAT_WS(' ', AuthorFirstName, AuthorMiddleName, AuthorLastName) AS Author
FROM Authors
WHERE AuthID=
   (
      SELECT ab.AuthID
      FROM AuthorArticle AS ab, Articles AS b
      WHERE ab.ArticleID=b.ArticleID AND ArticleTitle='AI'
   );








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