在PL/SQL代码中使用替换变量

Question

我正在使用SQL Developer并编写此PL/SQL代码。但是当我给出B选项时，我正在出错。请帮忙。

SET SERVEROUTPUT ON 

accept q_grade char prompt 'EnterGrade: ' 
DECLARE 
v_grade CHAR(1) := UPPER(&q_grade); 
v_appraisal VARCHAR(20); 

BEGIN 
v_appraisal := CASE v_grade WHEN v_grade = 'A' THEN 'Excellent' 
WHEN v_grade = 'B' THEN 'Good' 
WHEN v_grade = 'C' THEN 'FAIL' 
ELSE 'NO SUCH GRADES' 
END; 

DBMS_OUTPUT.PUT_LINE ('Grade: ' || v_grade || ' Appraisal ' ||v_appraisal); 

END; 
/

错误报告：

 
ORA-06550: line 2, column 26: 
PLS-00201: identifier 'B' must be declared 
ORA-06550: line 2, column 9: 
PL/SQL: Item ignored 
ORA-06550: line 6, column 21: 
PLS-00320: the declaration of the type of this expression is incomplete or malformed 
ORA-06550: line 6, column 1: 
PL/SQL: Statement ignored 
ORA-06550: line 12, column 57: 
PLS-00320: the declaration of the type of this expression is incomplete or malformed 
ORA-06550: line 12, column 21: 
PL/SQL: Statement ignored 
06550. 00000 - "line %s, column %s:\n%s" 
*Cause: Usually a PL/SQL compilation error. 
*Action: 

Answer 1

变化：

v_grade CHAR(1) := UPPER('&q_grade'); 

和

v_appraisal := CASE WHEN v_grade = 'A' THEN 'Excellent' 

Answer 2

您需要CASE声明后立即删除多余的v_grade：

BEGIN 
v_appraisal := CASE WHEN v_grade = 'A' THEN 'Excellent' 
/* -- here --------^ */