Oracle® Database SQL Language Reference 11g Release 2 (11.2) Part Number E17118-04 |
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PDF · Mobi · ePub |
A logical condition combines the results of two component conditions to produce a single result based on them or to invert the result of a single condition. Table 7-4 lists logical conditions.
Type of Condition | Operation | Examples |
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NOT |
Returns |
SELECT * FROM employees WHERE NOT (job_id IS NULL) ORDER BY employee_id; SELECT * FROM employees WHERE NOT (salary BETWEEN 1000 AND 2000) ORDER BY employee_id; |
AND |
Returns |
SELECT * FROM employees WHERE job_id = 'PU_CLERK' AND department_id = 30 ORDER BY employee_id; |
OR |
Returns |
SELECT * FROM employees WHERE job_id = 'PU_CLERK' OR department_id = 10 ORDER BY employee_id; |
Table 7-5 shows the result of applying the NOT
condition to an expression.
Table 7-6 shows the results of combining the AND
condition to two expressions.
AND | TRUE | FALSE | UNKNOWN |
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TRUE |
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FALSE |
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UNKNOWN |
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For example, in the WHERE
clause of the following SELECT
statement, the AND
logical condition is used to ensure that only those hired before 2004 and earning more than $2500 a month are returned:
SELECT * FROM employees WHERE hire_date < TO_DATE('01-JAN-2004', 'DD-MON-YYYY') AND salary > 2500 ORDER BY employee_id;
Table 7-7 shows the results of applying OR
to two expressions.
OR | TRUE | FALSE | UNKNOWN |
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TRUE |
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FALSE |
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UNKNOWN |
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For example, the following query returns employees who have a 40% commission rate or a salary greater than $20,000:
SELECT employee_id FROM employees WHERE commission_pct = .4 OR salary > 20000 ORDER BY employee_id;