逻辑运算符 下表显示了PL/SQL支持的逻辑运算符。所有这些操作符布尔运算,并产生布尔结果。假设变量A=true,变量B=false,那么: 运算符 | 描述 | 示例 | and | 称为逻辑AND运算。如果两个操作数为true,则条件为true | (A and B) 结果为 false. | or | 所谓的逻辑或操作。如果任何两个操作数为true,则条件变为true | (A or B) 结果为 true. | not | 所谓逻辑非运算符。用于反向操作数的逻辑状态。如果条件为true,那么逻辑非运算符将使它为false | not (A and B) 结果为 true. | 运算符:DECLARE a boolean := true; b boolean := false;BEGIN IF (a AND b) THENdbms_output.put_line('Line 1 - Condition is true'); END IF; IF (a OR b) THENdbms_output.put_line('Line 2 - Condition is true'); END IF; IF (NOT a) THENdbms_output.put_line('Line 3 - a is not true'); ELSEdbms_output.put_line('Line 3 - a is true'); END IF; IF (NOT b) THENdbms_output.put_line('Line 4 - b is not true'); ELSEdbms_output.put_line('Line 4 - b is true'); END IF;END;/当上述代码在SQL提示符执行时,它产生了以下结果:
Line 2 - Condition is trueLine 3 - a is trueLine 4 - b is not truePL/SQL procedure successfully completed.
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