Difference between revisions of "SELECT"

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A SELECT statement gets data from a table. Each table contains rows and columns - you can SELECT some columns and ignore others
 
*The column names on the select line control which columns you get
 
*The FROM clause controls which table you access
 
The table <code>games</code> shows the year and the city hosting the Olympic Games.
 
<table border='1'>
 
<caption>Author</caption>
 
<tr> <th>AUTHOR_ID</th> <th>NAME</th> </tr>
 
<tr> <td align='right'>1</td> <td>Shevchenko</td>  </tr>
 
<tr> <td align='right'>2</td> <td>Franko</td></tr>
 
<tr> <td align='right'>3</td> <td>Lesya</td> </tr>
 
<tr> <td align='right'>4</td> <td>Nestaiko</td> </tr>
 
<tr> <td align='right'>5</td> <td>Vasyliv</td></tr>
 
</table>
 
<table border='1'>
 
<caption>Book</caption>
 
<tr> <th>BOOK_ID</th> <th>AUTHOR_ID</th> <th>NAME</th><th>TYPE</th></tr>
 
<tr> <td align='right'>1</td> <td>4</td>  <td>School adventures</td><td>Roman</td></tr>
 
<tr> <td align='right'>2</td> <td>3</td> <td>Forest song</td><td>Poema</td></tr>
 
<tr> <td align='right'>3</td> <td>1</td><td>Cobzar</td><td>Virshi</td></tr>
 
<tr> <td align='right'>4</td> <td>2</td><td>Stolen happiness</td> <td>Povist</td></tr>
 
<tr> <td align='right'>5</td> <td>4</td>  <td>Moon rabbits</td><td>Roman</td></tr>
 
<tr> <td align='right'>6</td> <td>4</td> <td>Sun rabbits</td><td>Roman</td></tr>
 
<tr> <td align='right'>7</td> <td>2</td><td>Fox Mykyta</td> <td>Poema</td></tr>
 
<tr> <td align='right'>8</td> <td>3</td><td>Cool baby</td> <td>Poema</td></tr>
 
<tr> <td align='right'>9</td> <td>4</td><td>Muhoos from Vasyukivka</td> <td>Roman</td></tr>
 
</table>
 
<div class=qu>
 
The SELECT statement returns results from a <i>table</i>.
 
In this example the table is <code>games</code> and the columns are
 
<code>yr</code> and <code>city</code>.
 
<div class=tidy>
 
DROP TABLE games;
 
</div>
 
<div class=setup>
 
CREATE TABLE Author(AUTHOR_ID INT, NAME VARCHAR(20));
 
INSERT INTO Author(AUTHOR_ID,NAME) VALUES (1,'Shevchenko');
 
INSERT INTO Author(AUTHOR_ID,NAME) VALUES (2,'Franko');
 
INSERT INTO Author(AUTHOR_ID,NAME) VALUES (3,'Lesya');
 
INSERT INTO Author(AUTHOR_ID,NAME) VALUES (4,'Nestaiko');
 
INSERT INTO Author(AUTHOR_ID,NAME) VALUES (5,'Vasyliv');
 
</div>
 
<div class=setup>
 
CREATE TABLE Book(BOOK_ID INT, AUTHOR_ID INT, NAME VARCHAR(30),TYPE VARCHAR(20));
 
INSERT INTO games(BOOK_ID,AUTHOR_ID,NAME,TYPE) VALUES (1,4,'School adventures','Roman');
 
INSERT INTO games(BOOK_ID,AUTHOR_ID,NAME,TYPE) VALUES (2,4,'Forest song','Poema');
 
INSERT INTO games(BOOK_ID,AUTHOR_ID,NAME,TYPE) VALUES (3,4,'Cobzar','Virshi');
 
INSERT INTO games(BOOK_ID,AUTHOR_ID,NAME,TYPE) VALUES (4,4,'Stolen happiness','Povist');
 
INSERT INTO games(BOOK_ID,AUTHOR_ID,NAME,TYPE) VALUES (5,4,'Moon rabbits','Roman');
 
INSERT INTO games(BOOK_ID,AUTHOR_ID,NAME,TYPE) VALUES (6,4,'Sun rabbits','Roman');
 
INSERT INTO games(BOOK_ID,AUTHOR_ID,NAME,TYPE) VALUES (7,4,'Fox Mykyta','Poema');
 
INSERT INTO games(BOOK_ID,AUTHOR_ID,NAME,TYPE) VALUES (8,4,'Cool baby','Poema');
 
INSERT INTO games(BOOK_ID,AUTHOR_ID,NAME,TYPE) VALUES (9,4,'MuhoosfromVasyukivka','Roman');
 
</div>
 
<div class=def>
 
SELECT NAME FROM Autor
 
</div>
 
</div>
 
  
===See also:===
 
*[[SELECT_basics | SELECT Tutorial]] - practice using the SELECT command
 
*[[SELECT_.._WHERE  |SELECT ... WHERE]] - the WHERE clause allows you to get some rows but not others
 

Latest revision as of 04:00, 17 April 2014

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