Admin: 1 версия

2010-05-26T10:16:48Z

1 версия

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==Choose specific columns==



<source lang="sql">
/*
mysql> select * from employee;
+----+-----------+----------+----------------------------+------+---------------+--------+-------+---------------------+
| id | firstname | lastname | title | age | yearofservice| salary | perks | email |
+----+-----------+----------+----------------------------+------+---------------+--------+-------+---------------------+
| 1 | John | Chen | Senior Programmer | 31 | 3| 120000 | 25000 | j@hotmail.ru |
| 2 | Jan | Pillai | Senior Programmer | 32 | 4| 110000 | 20000 | g@yahoo.ru |
| 3 | Ane | Pandit | Web Designer | 24 | 3| 90000 | 15000 | a@gmail.ru |
| 4 | Mary | Anchor | Web Designer | 27 | 2| 85000 | 15000 | m@mail.ru |
| 5 | Fred | King | Programmer | 32 | 3| 75000 | 15000 | f@net.ru |
| 6 | John | Mac | Programmer | 32 | 4| 80000 | 16000 | j@hotmail.ru |
| 7 | Arthur | Sam | Programmer | 28 | 2| 75000 | 14000 | e@yahoo.ru |
| 8 | Alok | Nanda | Programmer | 32 | 3| 70000 | 10000 | a@yahoo.ru |
| 9 | Susan | Ra | Multimedia Programmer | 32 | 4| 90000 | 15000 | h@gmail.ru |
| 10 | Paul | Simon | Multimedia Programmer | 23 | 1| 85000 | 12000 | ps@gmail.ru |
| 11 | Edward | Parhar | Multimedia Programmer | 30 | 2| 75000 | 15000 | a@hotmail.ru |
| 12 | Kim | Hunter | Senior Web Designer | 32 | 4| 110000 | 20000 | kim@coolmail.ru |
| 13 | Roger | Lewis | System Administrator | 32 | 3| 100000 | 13000 | roger@mail.ru |
| 14 | Danny | Gibson | System Administrator | 31 | 2| 90000 | 12000 | danny@hotmail.ru |
| 15 | Mike | Harper | Senior Marketing Executive | 36 | 1| 120000 | 28000 | m@gmail.ru |
| 16 | Mary | Sunday | Marketing Executive | 31 | 5| 90000 | 25000 | monica@bigmail.ru |
| 17 | Jack | Sim | Marketing Executive | 27 | 1| 70000 | 18000 | hal@gmail.ru |
| 18 | Joe | Irvine | Marketing Executive | 27 | 1| 72000 | 18000 | joseph@hotmail.ru |
| 19 | Henry | Ali | Customer Service Manager | 32 | 3| 70000 | 9000 | shahida@hotmail.ru |
| 20 | Peter | Champion | Finance Manager | 32 | 2| 120000 | 25000 | peter@yahoo.ru |
+----+-----------+----------+----------------------------+------+---------------+--------+-------+---------------------+
20 rows in set (0.01 sec)
mysql> SELECT firstname,lastName from employee where title="Programmer";
+-----------+----------+
| firstname | lastName |
+-----------+----------+
| Fred | King |
| John | Mac |
| Arthur | Sam |
| Alok | Nanda |
+-----------+----------+
4 rows in set (0.01 sec)

*/
Drop table employee;
CREATE TABLE employee (
id int unsigned not null auto_increment primary key,
firstname varchar(20),
lastname varchar(20),
title varchar(30),
age int,
yearofservice int,
salary int,
perks int,
email varchar(60)
);

INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("John", "Chen", "Senior Programmer", 31, 3, 120000, 25000, "j@hotmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Jan", "Pillai", "Senior Programmer", 32, 4, 110000, 20000, "g@yahoo.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Ane", "Pandit", "Web Designer", 24, 3, 90000, 15000, "a@gmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Mary", "Anchor", "Web Designer", 27, 2, 85000, 15000, "m@mail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Fred", "King", "Programmer", 32, 3, 75000, 15000, "f@net.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("John", "Mac", "Programmer", 32, 4, 80000, 16000, "j@hotmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Arthur", "Sam", "Programmer", 28, 2, 75000, 14000, "e@yahoo.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Alok", "Nanda", "Programmer", 32, 3, 70000, 10000, "a@yahoo.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Susan", "Ra", "Multimedia Programmer", 32, 4, 90000, 15000, "h@gmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Paul", "Simon", "Multimedia Programmer", 23, 1, 85000, 12000, "ps@gmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Edward", "Parhar", "Multimedia Programmer", 30, 2, 75000, 15000, "a@hotmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Kim", "Hunter", "Senior Web Designer", 32, 4, 110000, 20000, "kim@coolmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Roger", "Lewis", "System Administrator", 32, 3, 100000, 13000, "roger@mail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Danny", "Gibson", "System Administrator", 31, 2, 90000, 12000, "danny@hotmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Mike", "Harper", "Senior Marketing Executive", 36, 1, 120000, 28000, "m@gmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Mary", "Sunday", "Marketing Executive", 31, 5, 90000, 25000, "monica@bigmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Jack", "Sim", "Marketing Executive", 27, 1, 70000, 18000, "hal@gmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Joe", "Irvine", "Marketing Executive", 27, 1, 72000, 18000, "joseph@hotmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Henry", "Ali", "Customer Service Manager", 32, 3, 70000, 9000, "shahida@hotmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Peter", "Champion", "Finance Manager", 32, 2, 120000, 25000, "peter@yahoo.ru");

select * from employee;
SELECT firstname,lastName from employee where title="Programmer";

</source>

==Define and use variable in select clause==



<source lang="sql">
/*
mysql> SELECT * FROM report;
+---------+--------+-------+
| article | dealer | price |
+---------+--------+-------+
| 0001 | A | 4.45 |
| 0001 | B | 5.45 |
| 0002 | A | 16.67 |
| 0003 | B | 6.12 |
| 0003 | C | 2.78 |
| 0003 | D | 2.34 |
| 0004 | D | 21.29 |
+---------+--------+-------+
7 rows in set (0.02 sec)
mysql> /* Using User Variables */
mysql> SELECT @min_price:=MIN(price),@max_price:=MAX(price) FROM report;
+------------------------+------------------------+
| @min_price:=MIN(price) | @max_price:=MAX(price) |
+------------------------+------------------------+
| 2.34 | 21.29 |
+------------------------+------------------------+
1 row in set (0.00 sec)

*/
Drop table report;

CREATE TABLE report (
article INT(4) UNSIGNED ZEROFILL DEFAULT "0000" NOT NULL,
dealer CHAR(20) DEFAULT "" NOT NULL,
price DOUBLE(16,2) DEFAULT "0.00" NOT NULL,
PRIMARY KEY(article, dealer));

INSERT INTO report VALUES (1,"A",4.45),
(1,"B",5.45),
(2,"A",16.67),
(3,"B",6.12),
(3,"C",2.78),
(3,"D",2.34),
(4,"D",21.29);

SELECT * FROM report;
/* Using User Variables */
SELECT @min_price:=MIN(price),@max_price:=MAX(price) FROM report;

</source>

==Performing a Single Row INSERT==



<source lang="sql">
/*
mysql> Select * from Professor;
+-------------+---------------+
| ProfessorID | Name |
+-------------+---------------+
| 0 | Snail at work |
+-------------+---------------+
1 row in set (0.00 sec)

*/
/* Create the table */
Drop TABLE Professor;
CREATE TABLE Professor (
ProfessorID INT NOT NULL PRIMARY KEY,
Name VARCHAR(50) NOT NULL)
TYPE = InnoDB;
/* Real command */
INSERT INTO Professor (ProfessorID, Name)
VALUES (0, "Snail at work");

/* Check the result */
Select * from Professor;

</source>

==Performing Mathematics==



<source lang="sql">
/* Prepare the data */
DROP TABLE Exam;
CREATE TABLE Exam (
StudentID INT NOT NULL,
ExamID INT NOT NULL,
Mark INT,
IfPassed SMALLINT
)TYPE = InnoDB;
/* Insert data for testing */
INSERT INTO Exam (StudentID,ExamID,Mark,IfPassed) VALUES (1,1,55,1);
INSERT INTO Exam (StudentID,ExamID,Mark,IfPassed) VALUES (1,2,73,0);
INSERT INTO Exam (StudentID,ExamID,Mark,IfPassed) VALUES (2,3,44,1);
/* Real command */
SELECT StudentID, ExamID, Mark * IfPassed AS MarkIfPassed FROM Exam;

</source>

==Reference column in select command==



<source lang="sql">
/*
mysql> Drop table Bird;
Query OK, 0 rows affected (0.00 sec)
mysql> CREATE TABLE Bird (
-> name VARCHAR(20),
-> owner VARCHAR(20),
-> species VARCHAR(20),
-> sex CHAR(1),
-> birth DATE,
-> death DATE
-> );
Query OK, 0 rows affected (0.06 sec)
mysql> INSERT INTO Bird VALUES ("BlueBird","Joe","Car","f","1999-03-30",NULL);
Query OK, 1 row affected (0.01 sec)
mysql> INSERT INTO Bird VALUES ("RedBird","Yin","Bus","m","1979-03-30",NULL);
Query OK, 1 row affected (0.00 sec)
mysql> select * from Bird;
+----------+-------+---------+------+------------+-------+
| name | owner | species | sex | birth | death |
+----------+-------+---------+------+------------+-------+
| BlueBird | Joe | Car | f | 1999-03-30 | NULL |
| RedBird | Yin | Bus | m | 1979-03-30 | NULL |
+----------+-------+---------+------+------------+-------+
2 rows in set (0.00 sec)
mysql> SELECT name, birth FROM Bird;
+----------+------------+
| name | birth |
+----------+------------+
| BlueBird | 1999-03-30 |
| RedBird | 1979-03-30 |
+----------+------------+
2 rows in set (0.01 sec)

*/
Drop table Bird;
CREATE TABLE Bird (
name VARCHAR(20),
owner VARCHAR(20),
species VARCHAR(20),
sex CHAR(1),
birth DATE,
death DATE
);

INSERT INTO Bird VALUES ("BlueBird","Joe","Car","f","1999-03-30",NULL);
INSERT INTO Bird VALUES ("RedBird","Yin","Bus","m","1979-03-30",NULL);

select * from Bird;

SELECT name, birth FROM Bird;

</source>

==Retrieve all columns in a table==



<source lang="sql">
/*
mysql> select * from student ORDER BY first_name, last_name ASC;
+-----------+------------+-----------+
| StudentID | first_name | last_name |
+-----------+------------+-----------+
| 5 | Anna | Wolff |
| 4 | Bruce | Lee |
| 3 | Emily | Scarlett |
| 2 | Gary | Burton |
| 1 | John | Jones |
| 7 | Steve | Alaska |
| 6 | Vic | Andrews |
+-----------+------------+-----------+
7 rows in set (0.02 sec)

*/
Drop table Student;
CREATE TABLE Student (
StudentID INT NOT NULL PRIMARY KEY,
first_name VARCHAR(50) NOT NULL,
last_name VARCHAR(50) NOT NULL

)TYPE = InnoDB;

INSERT INTO Student (StudentID,first_name, last_name) VALUES (1,"John", "Jones");
INSERT INTO Student (StudentID,first_name, last_name) VALUES (2,"Gary", "Burton");
INSERT INTO Student (StudentID,first_name, last_name) VALUES (3,"Emily", "Scarlett");
INSERT INTO Student (StudentID,first_name, last_name) VALUES (4,"Bruce", "Lee");
INSERT INTO Student (StudentID,first_name, last_name) VALUES (5,"Anna", "Wolff");
INSERT INTO Student (StudentID,first_name, last_name) VALUES (6,"Vic", "Andrews");
INSERT INTO Student (StudentID,first_name, last_name) VALUES (7,"Steve", "Alaska");

select * from student ORDER BY first_name, last_name ASC;

</source>

==Select clause with condition==



<source lang="sql">
/*mysql> select * from employee;
+----+-----------+----------+----------------------------+------+---------------+--------+-------+---------------------+
| id | firstname | lastname | title | age | yearofservice| salary | perks | email |
+----+-----------+----------+----------------------------+------+---------------+--------+-------+---------------------+
| 1 | John | Chen | Senior Programmer | 31 | 3| 120000 | 25000 | j@hotmail.ru |
| 2 | Jan | Pillai | Senior Programmer | 32 | 4| 110000 | 20000 | g@yahoo.ru |
| 3 | Ane | Pandit | Web Designer | 24 | 3| 90000 | 15000 | a@gmail.ru |
| 4 | Mary | Anchor | Web Designer | 27 | 2| 85000 | 15000 | m@mail.ru |
| 5 | Fred | King | Programmer | 32 | 3| 75000 | 15000 | f@net.ru |
| 6 | John | Mac | Programmer | 32 | 4| 80000 | 16000 | j@hotmail.ru |
| 7 | Arthur | Sam | Programmer | 28 | 2| 75000 | 14000 | e@yahoo.ru |
| 8 | Alok | Nanda | Programmer | 32 | 3| 70000 | 10000 | a@yahoo.ru |
| 9 | Susan | Ra | Multimedia Programmer | 32 | 4| 90000 | 15000 | h@gmail.ru |
| 10 | Paul | Simon | Multimedia Programmer | 23 | 1| 85000 | 12000 | ps@gmail.ru |
| 11 | Edward | Parhar | Multimedia Programmer | 30 | 2| 75000 | 15000 | a@hotmail.ru |
| 12 | Kim | Hunter | Senior Web Designer | 32 | 4| 110000 | 20000 | kim@coolmail.ru |
| 13 | Roger | Lewis | System Administrator | 32 | 3| 100000 | 13000 | roger@mail.ru |
| 14 | Danny | Gibson | System Administrator | 31 | 2| 90000 | 12000 | danny@hotmail.ru |
| 15 | Mike | Harper | Senior Marketing Executive | 36 | 1| 120000 | 28000 | m@gmail.ru |
| 16 | Mary | Sunday | Marketing Executive | 31 | 5| 90000 | 25000 | monica@bigmail.ru |
| 17 | Jack | Sim | Marketing Executive | 27 | 1| 70000 | 18000 | hal@gmail.ru |
| 18 | Joe | Irvine | Marketing Executive | 27 | 1| 72000 | 18000 | joseph@hotmail.ru |
| 19 | Henry | Ali | Customer Service Manager | 32 | 3| 70000 | 9000 | shahida@hotmail.ru |
| 20 | Peter | Champion | Finance Manager | 32 | 2| 120000 | 25000 | peter@yahoo.ru |
+----+-----------+----------+----------------------------+------+---------------+--------+-------+---------------------+
20 rows in set (0.00 sec)
mysql> SELECT firstname, lastName from employee where age > 32;
+-----------+----------+
| firstname | lastName |
+-----------+----------+
| Mike | Harper |
+-----------+----------+
1 row in set (0.00 sec)
*/
Drop table employee;
CREATE TABLE employee (
id int unsigned not null auto_increment primary key,
firstname varchar(20),
lastname varchar(20),
title varchar(30),
age int,
yearofservice int,
salary int,
perks int,
email varchar(60)
);

INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("John", "Chen", "Senior Programmer", 31, 3, 120000, 25000, "j@hotmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Jan", "Pillai", "Senior Programmer", 32, 4, 110000, 20000, "g@yahoo.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Ane", "Pandit", "Web Designer", 24, 3, 90000, 15000, "a@gmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Mary", "Anchor", "Web Designer", 27, 2, 85000, 15000, "m@mail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Fred", "King", "Programmer", 32, 3, 75000, 15000, "f@net.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("John", "Mac", "Programmer", 32, 4, 80000, 16000, "j@hotmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Arthur", "Sam", "Programmer", 28, 2, 75000, 14000, "e@yahoo.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Alok", "Nanda", "Programmer", 32, 3, 70000, 10000, "a@yahoo.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Susan", "Ra", "Multimedia Programmer", 32, 4, 90000, 15000, "h@gmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Paul", "Simon", "Multimedia Programmer", 23, 1, 85000, 12000, "ps@gmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Edward", "Parhar", "Multimedia Programmer", 30, 2, 75000, 15000, "a@hotmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Kim", "Hunter", "Senior Web Designer", 32, 4, 110000, 20000, "kim@coolmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Roger", "Lewis", "System Administrator", 32, 3, 100000, 13000, "roger@mail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Danny", "Gibson", "System Administrator", 31, 2, 90000, 12000, "danny@hotmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Mike", "Harper", "Senior Marketing Executive", 36, 1, 120000, 28000, "m@gmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Mary", "Sunday", "Marketing Executive", 31, 5, 90000, 25000, "monica@bigmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Jack", "Sim", "Marketing Executive", 27, 1, 70000, 18000, "hal@gmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Joe", "Irvine", "Marketing Executive", 27, 1, 72000, 18000, "joseph@hotmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Henry", "Ali", "Customer Service Manager", 32, 3, 70000, 9000, "shahida@hotmail.ru");
INSERT INTO employee (firstname, lastName, title, age, yearofservice, salary, perks, email) values ("Peter", "Champion", "Finance Manager", 32, 2, 120000, 25000, "peter@yahoo.ru");
select * from employee;

SELECT firstname, lastName from employee where age > 32;

</source>

==Simple Retrieval: Returning All Columns==



<source lang="sql">
/*
mysql> CREATE TABLE Student (
-> StudentID INT NOT NULL PRIMARY KEY,
-> Name VARCHAR(50) NOT NULL
-> )TYPE = InnoDB;
Query OK, 0 rows affected, 1 warning (0.08 sec)
mysql> /* Insert data for testing */
mysql> INSERT INTO Student (StudentID,Name) VALUES (1,"Joe Wang");
Query OK, 1 row affected (0.06 sec)
mysql> INSERT INTO Student (StudentID,Name) VALUES (2,"Cory But");
Query OK, 1 row affected (0.02 sec)
mysql> INSERT INTO Student (StudentID,Name) VALUES (3,"JJ Harvests");
Query OK, 1 row affected (0.04 sec)
mysql> /* Real command */
mysql> SELECT * FROM Student;
+-----------+-------------+
| StudentID | Name |
+-----------+-------------+
| 1 | Joe Wang |
| 2 | Cory But |
| 3 | JJ Harvests |
+-----------+-------------+
3 rows in set (0.03 sec)

*/
/* Prepare the data */
DROP TABLE Student;
CREATE TABLE Student (
StudentID INT NOT NULL PRIMARY KEY,
Name VARCHAR(50) NOT NULL
)TYPE = InnoDB;

/* Insert data for testing */
INSERT INTO Student (StudentID,Name) VALUES (1,"Joe Wang");
INSERT INTO Student (StudentID,Name) VALUES (2,"Cory But");
INSERT INTO Student (StudentID,Name) VALUES (3,"JJ Harvests");

/* Real command */
SELECT * FROM Student;

</source>

==Simple Retrieval:Returning a Single Column==



<source lang="sql">
/*
mysql> /* Prepare the data */
mysql> DROP TABLE Student;
Query OK, 0 rows affected (0.06 sec)
mysql> CREATE TABLE Student (
-> StudentID INT NOT NULL PRIMARY KEY,
-> Name VARCHAR(50) NOT NULL
-> )TYPE = InnoDB;
Query OK, 0 rows affected, 1 warning (0.11 sec)
mysql> /* Insert data for testing */
mysql> INSERT INTO Student (StudentID,Name) VALUES (1,"Joe Wang");
Query OK, 1 row affected (0.04 sec)
mysql> INSERT INTO Student (StudentID,Name) VALUES (2,"Cory But");
Query OK, 1 row affected (0.03 sec)
mysql> INSERT INTO Student (StudentID,Name) VALUES (3,"JJ Harvests");
Query OK, 1 row affected (0.06 sec)
mysql> /* Real command */
mysql> SELECT Name FROM Student;
+-------------+
| Name |
+-------------+
| Joe Wang |
| Cory But |
| JJ Harvests |
+-------------+
3 rows in set (0.01 sec)

*/
/* Prepare the data */
DROP TABLE Student;
CREATE TABLE Student (
StudentID INT NOT NULL PRIMARY KEY,
Name VARCHAR(50) NOT NULL
)TYPE = InnoDB;

/* Insert data for testing */
INSERT INTO Student (StudentID,Name) VALUES (1,"Joe Wang");
INSERT INTO Student (StudentID,Name) VALUES (2,"Cory But");
INSERT INTO Student (StudentID,Name) VALUES (3,"JJ Harvests");

/* Real command */
SELECT Name FROM Student;

</source>

==Simple Retrieval:Returning Multiple Columns==



<source lang="sql">
/*
mysql> /* Prepare the data */
mysql> DROP TABLE Student;
Query OK, 0 rows affected (0.07 sec)
mysql> CREATE TABLE Student (
-> StudentID INT NOT NULL PRIMARY KEY,
-> Name VARCHAR(50) NOT NULL
-> )TYPE = InnoDB;
Query OK, 0 rows affected, 1 warning (0.07 sec)
mysql> /* Insert data for testing */
mysql> INSERT INTO Student (StudentID,Name) VALUES (1,"Joe Wang");
Query OK, 1 row affected (0.02 sec)
mysql> INSERT INTO Student (StudentID,Name) VALUES (2,"Cory But");
Query OK, 1 row affected (0.03 sec)
mysql> INSERT INTO Student (StudentID,Name) VALUES (3,"JJ Harvests");
Query OK, 1 row affected (0.05 sec)
mysql> /* Real command */
mysql> SELECT StudentID, Name FROM Student;
+-----------+-------------+
| StudentID | Name |
+-----------+-------------+
| 1 | Joe Wang |
| 2 | Cory But |
| 3 | JJ Harvests |
+-----------+-------------+
3 rows in set (0.00 sec)
*/
/* Prepare the data */
DROP TABLE Student;
CREATE TABLE Student (
StudentID INT NOT NULL PRIMARY KEY,
Name VARCHAR(50) NOT NULL
)TYPE = InnoDB;

/* Insert data for testing */
INSERT INTO Student (StudentID,Name) VALUES (1,"Joe Wang");
INSERT INTO Student (StudentID,Name) VALUES (2,"Cory But");
INSERT INTO Student (StudentID,Name) VALUES (3,"JJ Harvests");

/* Real command */
SELECT StudentID, Name FROM Student;

</source>

==Use defined variable in new select clause==



<source lang="sql">
/*
mysql> SELECT * FROM report;
+---------+--------+-------+
| article | dealer | price |
+---------+--------+-------+
| 0001 | A | 4.45 |
| 0001 | B | 5.45 |
| 0002 | A | 16.67 |
| 0003 | B | 6.12 |
| 0003 | C | 2.78 |
| 0003 | D | 2.34 |
| 0004 | D | 21.29 |
+---------+--------+-------+
7 rows in set (0.00 sec)
mysql> SELECT @min_price:=MIN(price),@max_price:=MAX(price) FROM report;
+------------------------+------------------------+
| @min_price:=MIN(price) | @max_price:=MAX(price) |
+------------------------+------------------------+
| 2.34 | 21.29 |
+------------------------+------------------------+
1 row in set (0.00 sec)
mysql> /* Using User Variables */
mysql> SELECT * FROM report WHERE price=@min_price OR price=@max_price;
+---------+--------+-------+
| article | dealer | price |
+---------+--------+-------+
| 0003 | D | 2.34 |
| 0004 | D | 21.29 |
+---------+--------+-------+
2 rows in set (0.00 sec)

*/
Drop table report;

CREATE TABLE report (
article INT(4) UNSIGNED ZEROFILL DEFAULT "0000" NOT NULL,
dealer CHAR(20) DEFAULT "" NOT NULL,
price DOUBLE(16,2) DEFAULT "0.00" NOT NULL,
PRIMARY KEY(article, dealer));

INSERT INTO report VALUES (1,"A",4.45),
(1,"B",5.45),
(2,"A",16.67),
(3,"B",6.12),
(3,"C",2.78),
(3,"D",2.34),
(4,"D",21.29);

SELECT * FROM report;
SELECT @min_price:=MIN(price),@max_price:=MAX(price) FROM report;

/* Using User Variables */
SELECT * FROM report WHERE price=@min_price OR price=@max_price;

</source>

SQL/MySQL/Select Clause/Select - История изменений

в 13:46, 26 мая 2010

Admin: 1 версия

← Предыдущая	Версия 13:46, 26 мая 2010
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