所搜索的CASE語句冇有選擇WHEN子句包含給布爾值的搜索條件。

語法:

在PL/SQL搜查case語句語法是：

CASE
    WHEN selector = 'value1' THEN S1;
    WHEN selector = 'value2' THEN S2;
    WHEN selector = 'value3' THEN S3;
    ...
    ELSE Sn;  -- default case
END CASE;

流程圖：

示例:

DECLARE
   grade char(1) := 'B';
BEGIN
   case 
      when grade = 'A' then dbms_output.put_line('Excellent');
      when grade = 'B' then dbms_output.put_line('Very good');
      when grade = 'C' then dbms_output.put_line('Well done');
      when grade = 'D' then dbms_output.put_line('You passed');
      when grade = 'F' then dbms_output.put_line('Better try again');
      else dbms_output.put_line('No such grade');
   end case;
END;
/

當上述代碼在SQL提示符執行時，它產生了以下結果：

Very good

PL/SQL procedure successfully completed.