SQL/MySQL/Procedure Function/Buildin Functions
Содержание
Call buildin math function in your procedure
mysql> delimiter $$
mysql>
mysql>
mysql> CREATE PROCEDURE myProc()
-> BEGIN
-> DECLARE my_big_integer int DEFAULT 2;
->
-> SET my_big_integer=POWER(my_big_integer,3);
->
-> select my_big_integer;
-> END$$
Query OK, 0 rows affected (0.00 sec)
mysql> delimiter ;
mysql>
mysql> call myProc();
+----------------+
| my_big_integer |
+----------------+
| 8 |
+----------------+
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.00 sec)
mysql> drop procedure myProc;
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql>
Check MySQL version
mysql>
mysql> delimiter $$
mysql>
mysql>
mysql> CREATE PROCEDURE myProc()
-> BEGIN
->
-> IF (CAST(SUBSTR(version(),1,3) AS DECIMAL(2,1)) <5.0) THEN
-> SELECT "MySQL versions earlier than 5.0";
-> ELSE
-> SELECT "Thank you are running 5.0 or higher!";
-> END IF;
->
-> END$$
Query OK, 0 rows affected (0.02 sec)
mysql>
mysql> delimiter ;
mysql> call myProc();
+--------------------------------------+
| Thank you are running 5.0 or higher! |
+--------------------------------------+
| Thank you are running 5.0 or higher! |
+--------------------------------------+
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.02 sec)
mysql> drop procedure myProc;
Query OK, 0 rows affected (0.00 sec)
mysql>
Return the file size by using the LOAD_FILE function
mysql>
mysql> delimiter $$
mysql>
mysql> CREATE PROCEDURE filesize(in_file_name VARCHAR(128))
->
-> BEGIN
-> DECLARE mytext TEXT;
-> SET mytext=LOAD_FILE(in_file_name);
-> SELECT in_file_name||" contains "||length(mytext)||" bytes"
-> AS output;
-> END$$
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql> delimiter ;
mysql> call filesize("a.txt");
+--------+
| output |
+--------+
| NULL |
+--------+
1 row in set (0.00 sec)
Query OK, 0 rows affected, 2 warnings (0.00 sec)
mysql> drop procedure filesize;
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql>
Use Build-in SUM function in a procedure
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 (0.03 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 (0.00 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 (0.00 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> delimiter $$
mysql> CREATE PROCEDURE myProc(in_id INT)
-> READS SQL DATA
-> BEGIN
-> DECLARE total_salary NUMERIC(8,2);
->
-> SELECT SUM(salary)
-> INTO total_salary
-> FROM employee
-> WHERE id=in_id;
->
-> SELECT CONCAT("Total salary ",in_id," is ",total_salary);
-> END$$
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql>
mysql> delimiter ;
mysql>
mysql> call myProc(3);
+---------------------------------------------------+
| CONCAT("Total salary ",in_id," is ",total_salary) |
+---------------------------------------------------+
| Total salary 3 is 6544.78 |
+---------------------------------------------------+
1 row in set (0.00 sec)
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> DROP PROCEDURE myProc;
Query OK, 0 rows affected (0.02 sec)
mysql>
mysql>
mysql>
mysql>
mysql> drop table Employee;
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql>
Using String functions in a user-defined function
mysql>
mysql> delimiter $$
mysql>
mysql> CREATE FUNCTION myFunction
-> (in_string VARCHAR(255),
-> in_find_str VARCHAR(20),
-> in_repl_str VARCHAR(20))
->
-> RETURNS VARCHAR(255)
-> BEGIN
-> DECLARE l_new_string VARCHAR(255);
-> DECLARE l_find_pos INT;
->
-> SET l_find_pos=INSTR(in_string,in_find_str);
->
-> IF (l_find_pos>0) THEN
-> SET l_new_string=INSERT(in_string,l_find_pos,LENGTH(in_find_str),in_repl_str);
-> ELSE
-> SET l_new_string=in_string;
-> END IF;
-> RETURN(l_new_string);
->
-> END$$
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql> delimiter ;
mysql> select myFunction("ABC","A","Z");
+---------------------------+
| myFunction("ABC","A","Z") |
+---------------------------+
| ZBC |
+---------------------------+
1 row in set (0.00 sec)
mysql> drop function myFunction;
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql>