How to use while loop in oracle

WHILE loops are used in Oracle to repeatedly execute a block of code when a specific condition is met. The syntax is: WHILE -- a block of code to be executed repeatedly END WHILE; The components include: Condition: a Boolean expression that determines whether the loop continues. Loop body: The block of code to be executed if the condition is true.

How to use WHILE loop in Oracle

WHILE loop is a control flow statement that is used to repeatedly execute a section when certain conditions are met code block. In Oracle, the syntax of the WHILE loop is as follows:

<code>WHILE <条件>
  -- 要重复执行的代码块
END WHILE;</code>

Each component is explained in detail below:

Condition:

This is a Boolean expression Formula, determines whether the loop continues to execute. If the condition is true, the loop body is executed; otherwise, the loop terminates.

Loop body:

This is the block of code to be executed if the condition is true. The loop body is executed repeatedly until the condition is false.

Example:

The following example creates a WHILE loop that continuously prompts the user for input as long as the user types a non-empty string:

<code class="sql">DECLARE
  input VARCHAR2(20);
BEGIN
  -- 循环继续，直到用户输入空字符串
  WHILE input IS NOT NULL
  LOOP
    -- 提示用户输入
    DBMS_OUTPUT.PUT_LINE('请输入一个字符串：');
    -- 从用户接收输入
    input := UPPER(DBMS_INPUT.GET_LINE());
    -- 如果输入为空，则退出循环
    EXIT WHEN input IS NULL;
    -- 否则，打印输入字符串的大写形式
    DBMS_OUTPUT.PUT_LINE('您输入的字符串的大写形式是：' || input);
  END LOOP;
END;
/</code>

Note:

• The WHILE loop will continue to execute until the condition is false. Therefore, make sure that the condition will eventually become false to avoid an infinite loop.
• You can use the EXIT statement within the loop body to explicitly exit the loop.

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