Laboratoriya ishi Mavzu: sql da funksiyalar yaratish. Ishdan maqsad

21-22-23.Laboratoriya ishi
Mavzu: SQL da funksiyalar yaratish.
Ishdan maqsad: SQL da funksiyalar yaratish bo`yicha ko`nikmaga ega bo`lish.
Masalani qo`yilishi: Berilgan predmet soha ma`lumotlar bazasidagi barcha

ob`yektlarni ustida VIEWlar yaratish asosida amallarini bajarish.

Uslubiy ko`rsatmalar: Funksiyalar (FUNCTION) - protseduraga o'xshash, bu biz qayta-qayta ishlatmoqchi bo'lgan ba'zi SQL kod. Funktsiya va protsedura o'rtasidagi farq shundan iboratki, funktsiya faqat bitta parametrni qaytaradi va funktsiya "Call" qilmasdan nomi bilan chaqiriladi. Shuning uchun funktsiya SQL so'rovlarida ishlatilishi mumkin.

mysql> DELIMITER ##

mysql> SHOW DATABASES;

-> ##

+----------------------------------+

| Database |

+----------------------------------+

| information_schema |

| mehmonxona |

| mysql |

| ofis_xarajatlarini_hisobga_olish |

| sayohatlar_agentligi |

| sirk |

| test |

| zaxira_buyum_sotadigan_kampaniya |

+----------------------------------+

8 rows in set (2.50 sec)

DETERMINISTIC

BEGIN

DECLARE RESULT INT;

SET RESULT=A/B;

RETURN (RES' at line 1

mysql> CREATE FUNCTION BOLISHH(A INT, B INT) RETURNS INT

-> DETERMINISTIC

-> BEGIN

-> DECLARE RESULT INT;

-> SET RESULT=A/B;

-> RETURN (RESULT);

-> END ##

Query OK, 0 rows affected (2.36 sec)

mysql> create function kopaytir(a int, b int) returns int

-> DETERMINISTIC BEGIN DECLARE RESULT INT ;

-> SET RESULT=a*b;

-> return(result);

-> end%%

Query OK, 0 rows affected (1.39 sec)

mysql> create function qoshish(a int, b int) returns int

-> DETERMINISTIC BEGIN DECLARE RESULT INT ;

-> SET RESULT=a-b;

-> return(result);

-> end%%

Query OK, 0 rows affected (0.00 sec)

mysql> select qoshish(51,25)%%

+----------------+

| qoshish(51,25) |

+----------------+

| 26 |

+----------------+

1 row in set (1.97 sec)

mysql>

mysql> create function ayrish(a int, b int) returns int

-> DETERMINISTIC BEGIN DECLARE RESULT INT ;

-> SET RESULT=a+b;

-> return(result);

-> end%%

Query OK, 0 rows affected (2.64 sec)

mysql> select ayrish(100,25)%%

+----------------+

| ayrish(100,25) |

+----------------+

| 125 |

+----------------+

1 row in set (0.00 sec)

mysql>

TAMOM.

E’TIBORINGIZ UCHUN RAHMAT.