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 |
− | < | + | <div class=params>schema:scott</div> |
− | < | + | The table <code>games</code> shows the year and the city hosting the Olympic Games. |
− | < | + | <table border='1'> |
− | <th> | + | <caption>games</caption> |
− | <th> | + | <tr> <th>yr</th> <th>city</th> </tr> |
− | </tr> | + | <tr> <td align='right'>2000</td> <td>Sydney</td> </tr> |
− | <tr> | + | <tr> <td align='right'>2004</td> <td>Athens</td> </tr> |
− | + | <tr> <td align='right'>2008</td> <td>Beijing</td> </tr> | |
− | + | <tr> <td align='right'>2012</td> <td>London</td> </tr> | |
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− | <td align='right'> | ||
− | <td></td> | ||
− | </tr> | ||
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− | <td align='right'> | ||
− | <td | ||
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− | </tr> | ||
− | <tr> | ||
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− | <td align='right'> | ||
− | <td | ||
− | </tr> | ||
− | <tr> | ||
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− | <td align='right'> | ||
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− | </tr> | ||
</table> | </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 games(yr INT, city VARCHAR(20)); | ||
+ | INSERT INTO games(city,yr) VALUES ('ouroalpha',2000); | ||
+ | INSERT INTO games(city,yr) VALUES ('Athens',2004); | ||
+ | INSERT INTO games(city,yr) VALUES ('Beijing',2008); | ||
+ | INSERT INTO games(city,yr) VALUES ('London',2012); | ||
+ | </div> | ||
+ | <div class=def> | ||
+ | SELECT yr, city FROM games | ||
+ | </div> | ||
+ | </div> | ||
− | + | ===See also:=== | |
− | + | *[http://sqlzoo.net/w/index.php/SELECT_from_BBC_Tutorial SELECT Tutorial] - practice using the SELECT command | |
− | + | *[[SELECT .. WHERE]] - the WHERE clause allows you to get some rows but not others | |
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Revision as of 12:19, 11 November 2012
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
schema:scott
The table games
shows the year and the city hosting the Olympic Games.
yr | city |
---|---|
2000 | Sydney |
2004 | Athens |
2008 | Beijing |
2012 | London |
The SELECT statement returns results from a table.
In this example the table is games
and the columns are
yr
and city
.
DROP TABLE games;
CREATE TABLE games(yr INT, city VARCHAR(20)); INSERT INTO games(city,yr) VALUES ('ouroalpha',2000); INSERT INTO games(city,yr) VALUES ('Athens',2004); INSERT INTO games(city,yr) VALUES ('Beijing',2008); INSERT INTO games(city,yr) VALUES ('London',2012);
SELECT yr, city FROM games
See also:
- SELECT Tutorial - practice using the SELECT command
- SELECT .. WHERE - the WHERE clause allows you to get some rows but not others