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。但当我给B作为选项时，我得到了一个错误。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

您需要在案例语句之后删除额外的v_等级：

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

Answer 2

改变：

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

和

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