MySQL Tutorial/Select Query/Column

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Column filter and Order by clause

mysql>
mysql> CREATE TABLE Topic(
    ->    TopicID     SMALLINT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    ->    Name        VARCHAR(50) NOT NULL,
    ->    InStock     SMALLINT UNSIGNED NOT NULL,
    ->    OnOrder     SMALLINT UNSIGNED NOT NULL,
    ->    Reserved    SMALLINT UNSIGNED NOT NULL,
    ->    Department  ENUM("Classical", "Popular") NOT NULL,
    ->    Category    VARCHAR(20) NOT NULL,
    ->    RowUpdate   TIMESTAMP NOT NULL
    -> );
Query OK, 0 rows affected (0.02 sec)
mysql>
mysql>
mysql> INSERT INTO Topic (Name,          InStock, OnOrder, Reserved, Department,   Category) VALUES
    ->                   ("Java",          10,      5,       3,        "Popular",    "Rock"),
    ->                   ("JavaScript",    10,      5,       3,        "Classical",  "Opera"),
    ->                   ("C Sharp",       17,      4,       1,        "Popular",    "Jazz"),
    ->                   ("C",             9,       4,       2,        "Classical",  "Dance"),
    ->                   ("C++",           24,      2,       5,        "Classical",  "General"),
    ->                   ("Perl",          16,      6,       8,        "Classical",  "Vocal"),
    ->                   ("Python",        2,       25,      6,        "Popular",    "Blues"),
    ->                   ("Php",           32,      3,       10,       "Popular",    "Jazz"),
    ->                   ("ASP.net",       12,      15,      13,       "Popular",    "Country"),
    ->                   ("VB.net",        5,       20,      10,       "Popular",    "New Age"),
    ->                   ("VC.net",        24,      11,      14,       "Popular",    "New Age"),
    ->                   ("UML",           42,      17,      17,       "Classical",  "General"),
    ->                   ("www.sqle.ru",25,      44,      28,       "Classical",  "Dance"),
    ->                   ("Oracle",        32,      15,      12,       "Classical",  "General"),
    ->                   ("Pl/SQL",        20,      10,      5,        "Classical",  "Opera"),
    ->                   ("Sql Server",    23,      12,      8,        "Classical",  "General");
Query OK, 16 rows affected (0.00 sec)
Records: 16  Duplicates: 0  Warnings: 0
mysql>
mysql> select * from Topic;
+---------+----------------+---------+---------+----------+------------+----------+---------------------+
| TopicID | Name           | InStock | OnOrder | Reserved | Department | Category | RowUpdate           |
+---------+----------------+---------+---------+----------+------------+----------+---------------------+
|       1 | Java           |      10 |       5 |        3 | Popular    | Rock     | 2007-07-23 19:09:43 |
|       2 | JavaScript     |      10 |       5 |        3 | Classical  | Opera    | 2007-07-23 19:09:43 |
|       3 | C Sharp        |      17 |       4 |        1 | Popular    | Jazz     | 2007-07-23 19:09:43 |
|       4 | C              |       9 |       4 |        2 | Classical  | Dance    | 2007-07-23 19:09:43 |
|       5 | C++            |      24 |       2 |        5 | Classical  | General  | 2007-07-23 19:09:43 |
|       6 | Perl           |      16 |       6 |        8 | Classical  | Vocal    | 2007-07-23 19:09:43 |
|       7 | Python         |       2 |      25 |        6 | Popular    | Blues    | 2007-07-23 19:09:43 |
|       8 | Php            |      32 |       3 |       10 | Popular    | Jazz     | 2007-07-23 19:09:43 |
|       9 | ASP.net        |      12 |      15 |       13 | Popular    | Country  | 2007-07-23 19:09:43 |
|      10 | VB.net         |       5 |      20 |       10 | Popular    | New Age  | 2007-07-23 19:09:43 |
|      11 | VC.net         |      24 |      11 |       14 | Popular    | New Age  | 2007-07-23 19:09:43 |
|      12 | UML            |      42 |      17 |       17 | Classical  | General  | 2007-07-23 19:09:43 |
|      13 | www.sqle.ru |      25 |      44 |       28 | Classical  | Dance    | 2007-07-23 19:09:43 |
|      14 | Oracle         |      32 |      15 |       12 | Classical  | General  | 2007-07-23 19:09:43 |
|      15 | Pl/SQL         |      20 |      10 |        5 | Classical  | Opera    | 2007-07-23 19:09:43 |
|      16 | Sql Server     |      23 |      12 |        8 | Classical  | General  | 2007-07-23 19:09:43 |
+---------+----------------+---------+---------+----------+------------+----------+---------------------+
16 rows in set (0.00 sec)
mysql>
mysql> SELECT Name, InStock, OnOrder
    -> FROM Topic
    -> WHERE InStock>20
    -> ORDER BY Name DESC;
+----------------+---------+---------+
| Name           | InStock | OnOrder |
+----------------+---------+---------+
| www.sqle.ru |      25 |      44 |
| VC.net         |      24 |      11 |
| UML            |      42 |      17 |
| Sql Server     |      23 |      12 |
| Php            |      32 |       3 |
| Oracle         |      32 |      15 |
| C++            |      24 |       2 |
+----------------+---------+---------+
7 rows in set (0.02 sec)
mysql>
mysql> drop table Topic;
Query OK, 0 rows affected (0.00 sec)


In MySQL you can refer to a column using any of the following forms

col_name
tbl_name.col_name
db_name.tbl_name.col_name


Restricting Columns: Ask for only certain columns to be returned

mysql>
mysql>
mysql> CREATE TABLE Employee(
    ->     id            int,
    ->     first_name    VARCHAR(15),
    ->     last_name     VARCHAR(15),
    ->     start_date    DATE,
    ->     end_date      DATE,
    ->     salary        FLOAT(8,2),
    ->     city          VARCHAR(10),
    ->     description   VARCHAR(15)
    -> );
Query OK, 0 rows affected (0.02 sec)
mysql>
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->              values (1,"Jason",    "Martin",  "19960725",  "20060725", 1234.56, "Toronto",  "Programmer");
Query OK, 1 row affected (0.01 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(2,"Alison",   "Mathews",  "19760321", "19860221", 6661.78, "Vancouver","Tester");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(3,"James",    "Smith",    "19781212", "19900315", 6544.78, "Vancouver","Tester");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(4,"Celia",    "Rice",     "19821024", "19990421", 2344.78, "Vancouver","Manager");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(5,"Robert",   "Black",    "19840115", "19980808", 2334.78, "Vancouver","Tester");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(6,"Linda",    "Green",    "19870730", "19960104", 4322.78,"New York",  "Tester");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(7,"David",    "Larry",    "19901231", "19980212", 7897.78,"New York",  "Manager");
Query OK, 1 row affected (0.02 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(8,"James",    "Cat",     "19960917",  "20020415", 1232.78,"Vancouver", "Tester");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> select * from Employee;
+------+------------+-----------+------------+------------+---------+-----------+-------------+
| id   | first_name | last_name | start_date | end_date   | salary  | city      | description |
+------+------------+-----------+------------+------------+---------+-----------+-------------+
|    1 | Jason      | Martin    | 1996-07-25 | 2006-07-25 | 1234.56 | Toronto   | Programmer  |
|    2 | Alison     | Mathews   | 1976-03-21 | 1986-02-21 | 6661.78 | Vancouver | Tester      |
|    3 | James      | Smith     | 1978-12-12 | 1990-03-15 | 6544.78 | Vancouver | Tester      |
|    4 | Celia      | Rice      | 1982-10-24 | 1999-04-21 | 2344.78 | Vancouver | Manager     |
|    5 | Robert     | Black     | 1984-01-15 | 1998-08-08 | 2334.78 | Vancouver | Tester      |
|    6 | Linda      | Green     | 1987-07-30 | 1996-01-04 | 4322.78 | New York  | Tester      |
|    7 | David      | Larry     | 1990-12-31 | 1998-02-12 | 7897.78 | New York  | Manager     |
|    8 | James      | Cat       | 1996-09-17 | 2002-04-15 | 1232.78 | Vancouver | Tester      |
+------+------------+-----------+------------+------------+---------+-----------+-------------+
8 rows in set (0.00 sec)
mysql>
mysql>
mysql>
mysql>
mysql> SELECT employee.city, employee.start_date, employee.first_name, employee.last_name
    ->  FROM employee
    ->  WHERE (employee.id = 1);
+---------+------------+------------+-----------+
| city    | start_date | first_name | last_name |
+---------+------------+------------+-----------+
| Toronto | 1996-07-25 | Jason      | Martin    |
+---------+------------+------------+-----------+
1 row in set (0.00 sec)
mysql>
mysql>
mysql>
mysql>
mysql> drop table Employee;
Query OK, 0 rows affected (0.00 sec)
mysql>


Using the full TABLE.COLUMN reference

mysql>
mysql> CREATE TABLE Employee(
    ->     id            int,
    ->     first_name    VARCHAR(15),
    ->     last_name     VARCHAR(15),
    ->     start_date    DATE,
    ->     end_date      DATE,
    ->     salary        FLOAT(8,2),
    ->     city          VARCHAR(10),
    ->     description   VARCHAR(15)
    -> );
Query OK, 0 rows affected (0.02 sec)
mysql>
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->              values (1,"Jason",    "Martin",  "19960725",  "20060725", 1234.56, "Toronto",  "Programmer");
Query OK, 1 row affected (0.01 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(2,"Alison",   "Mathews",  "19760321", "19860221", 6661.78, "Vancouver","Tester");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(3,"James",    "Smith",    "19781212", "19900315", 6544.78, "Vancouver","Tester");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(4,"Celia",    "Rice",     "19821024", "19990421", 2344.78, "Vancouver","Manager");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(5,"Robert",   "Black",    "19840115", "19980808", 2334.78, "Vancouver","Tester");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(6,"Linda",    "Green",    "19870730", "19960104", 4322.78,"New York",  "Tester");
Query OK, 1 row affected (0.01 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(7,"David",    "Larry",    "19901231", "19980212", 7897.78,"New York",  "Manager");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    ->               values(8,"James",    "Cat",     "19960917",  "20020415", 1232.78,"Vancouver", "Tester");
Query OK, 1 row affected (0.00 sec)
mysql>
mysql> select * from Employee;
+------+------------+-----------+------------+------------+---------+-----------+-------------+
| id   | first_name | last_name | start_date | end_date   | salary  | city      | description |
+------+------------+-----------+------------+------------+---------+-----------+-------------+
|    1 | Jason      | Martin    | 1996-07-25 | 2006-07-25 | 1234.56 | Toronto   | Programmer  |
|    2 | Alison     | Mathews   | 1976-03-21 | 1986-02-21 | 6661.78 | Vancouver | Tester      |
|    3 | James      | Smith     | 1978-12-12 | 1990-03-15 | 6544.78 | Vancouver | Tester      |
|    4 | Celia      | Rice      | 1982-10-24 | 1999-04-21 | 2344.78 | Vancouver | Manager     |
|    5 | Robert     | Black     | 1984-01-15 | 1998-08-08 | 2334.78 | Vancouver | Tester      |
|    6 | Linda      | Green     | 1987-07-30 | 1996-01-04 | 4322.78 | New York  | Tester      |
|    7 | David      | Larry     | 1990-12-31 | 1998-02-12 | 7897.78 | New York  | Manager     |
|    8 | James      | Cat       | 1996-09-17 | 2002-04-15 | 1232.78 | Vancouver | Tester      |
+------+------------+-----------+------------+------------+---------+-----------+-------------+
8 rows in set (0.00 sec)
mysql>
mysql>
mysql>
mysql> SELECT * FROM employee WHERE (employee.city = "Vancouver");
+------+------------+-----------+------------+------------+---------+-----------+-------------+
| id   | first_name | last_name | start_date | end_date   | salary  | city      | description |
+------+------------+-----------+------------+------------+---------+-----------+-------------+
|    2 | Alison     | Mathews   | 1976-03-21 | 1986-02-21 | 6661.78 | Vancouver | Tester      |
|    3 | James      | Smith     | 1978-12-12 | 1990-03-15 | 6544.78 | Vancouver | Tester      |
|    4 | Celia      | Rice      | 1982-10-24 | 1999-04-21 | 2344.78 | Vancouver | Manager     |
|    5 | Robert     | Black     | 1984-01-15 | 1998-08-08 | 2334.78 | Vancouver | Tester      |
|    8 | James      | Cat       | 1996-09-17 | 2002-04-15 | 1232.78 | Vancouver | Tester      |
+------+------------+-----------+------------+------------+---------+-----------+-------------+
5 rows in set (0.00 sec)
mysql>
mysql>
mysql>
mysql>
mysql> drop table Employee;
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql>