April 2025
Intermediate to advanced
356 pages
5h 20m
Italian
Content preview from SQL Pocket Guide, 4a edizione
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Capitolo 7. Operatori e funzioni
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Gli operatori e le funzioni vengono utilizzati per eseguire calcoli, confronti e trasformazioni all'interno di un'istruzione SQL. Questo capitolo fornisce esempi di codice per gli operatori e le funzioni più comuni.
La seguente query evidenzia cinque operatori (+, =, OR, BETWEEN, AND) e due funzioni (UPPER, YEAR):
-- Pay increases for employees
SELECT name, pay_rate + 5 AS new_pay_rate
FROM employees
WHERE UPPER(title) = 'ANALYST'
OR YEAR(start_date) BETWEEN 2016 AND 2018;
Oltre agli enunciati SELECT, gli operatori e le funzioni possono essere utilizzati anche negli enunciati INSERT, UPDATE e DELETE.
Questo capitolo comprende una sezione sugli Operatori e cinque sezioni sulle funzioni: Funzioni aggregate, Funzioni numeriche, Funzioni stringa, Funzioni data e ora e Funzioni null.
La Tabella 7-1 elenca gli operatori comuni e la Tabella 7-2 elenca le funzioni comuni.
| Operatori logici | Operatori di confronto (simboli) ... |
|---|
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