无涯教程-PL/SQL - Searched CASE 语句函数

搜索的CASE语句没有选择器，并且该语句的WHEN子句包含提供布尔值的搜索条件。

Searched CASE - 语法

PL/SQL中搜索到的case语句的语法为-

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

Searched CASE - 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; 
/

当以上代码在SQL提示符下执行时，将产生以下输出-

Very good  

PL/SQL procedure successfully completed. 

参考链接

https://www.learnfk.com/plsql/plsql-searched-case.html