The ELSE clause in PL/SQL specifies the alternative execution path when the condition is false in the IF-THEN-ELSE statement. The syntax is: IF condition THEN code block 1 ELSE code block 2 END IF. Its uses include specifying operations when a condition is false, handling different results, and handling special cases.
Usage of ELSE clause in PL/SQL
The ELSE clause is used in PL/SQL control statements (such as IF-THEN-ELSE) specifies an alternative execution path when the condition is false.
Syntax
1 2 3 4 5 | <code>IF condition THEN
-- 代码块 1 -- 如果条件为真,则执行
ELSE
-- 代码块 2 -- 如果条件为假,则执行
END IF;</code>
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Usage
The ELSE clause is used in the following situations:
- When you need to perform specific operations when conditions are not met.
- When a choice needs to be made between two or more possible outcomes.
- When you need to handle special situations where the condition is false.
Example
1 2 3 4 5 6 7 8 9 10 | <code>-- 检查一个数字是否是偶数
DECLARE
number NUMBER := 10;
BEGIN
IF number MOD 2 = 0 THEN
DBMS_OUTPUT.PUT_LINE( '该数字是偶数。' );
ELSE
DBMS_OUTPUT.PUT_LINE( '该数字是奇数。' );
END IF;
END ;</code>
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Output:
Note:
- The ELSE clause is optional. If not provided, control flow will continue with subsequent code execution when the condition is false.
- The ELSE clause can only be used with an IF statement.
- The ELSE clause can be nested within other IF statements.
- The ELSE clause can be used with the ELSIF clause to implement more complex branching logic.
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