case表達式詳解
阿新 • • 發佈：2017-09-21
clas com lec employ dbms pan lar ber log
CASE 表達式
---------格式一--------- CASE 條件表達式 WHEN 條件表達式結果1 THEN 語句段1 WHEN 條件表達式結果2 THEN 語句段2 ...... WHEN 條件表達式結果n THEN 語句段n [ELSE 條件表達式結果] END; ---------格式二--------- CASE WHEN 條件表達式1 THEN 語句段1 WHEN 條件表達式2 THEN 語句段2 ...... WHEN 條件表達式n THEN 語句段n [ELSE 語句段] END;
例4:
1 DECLARE 2 V_grade char(1) := UPPER(‘&p_grade‘); 3 V_appraisal VARCHAR2(20); 4 BEGIN 5 V_appraisal := 6 CASE v_grade 7 WHEN ‘A‘ THEN ‘Excellent‘ 8 WHEN ‘B‘ THEN ‘Very Good‘ 9 WHEN ‘C‘ THEN ‘Good‘ 10 ELSE ‘No such grade‘ 11 END; 12 DBMS_OUTPUT.PUT_LINE(‘Grade:‘||v_grade||‘ Appraisal: ‘|| v_appraisal);13 END;
例5:
1 DECLARE 2 v_first_name employees.first_name%TYPE; 3 v_job_id employees.job_id%TYPE; 4 v_salary employees.salary%TYPE; 5 v_sal_raise NUMBER(3,2); 6 BEGIN 7 SELECT first_name, job_id, salary INTO 8 v_first_name, v_job_id, v_salary 9 FROM employees WHERE employee_id = &emp_id;10 CASE 11 WHEN v_job_id = ‘PU_CLERK‘ THEN 12 IF v_salary < 3000 THEN v_sal_raise := .08; 13 ELSE v_sal_raise := .07; 14 END IF; 15 WHEN v_job_id = ‘SH_CLERK‘ THEN 16 IF v_salary < 4000 THEN v_sal_raise := .06; 17 ELSE v_sal_raise := .05; 18 END IF; 19 WHEN v_job_id = ‘ST_CLERK‘ THEN 20 IF v_salary < 3500 THEN v_sal_raise := .04; 21 ELSE v_sal_raise := .03; 22 END IF; 23 ELSE 24 DBMS_OUTPUT.PUT_LINE(‘該崗位不漲工資: ‘||v_job_id); 25 END CASE; 26 DBMS_OUTPUT.PUT_LINE(v_first_name||‘的崗位是‘||v_job_id 27 ||‘、的工資是‘||v_salary 28 ||‘、工資漲幅是‘||v_sal_raise); 29 END;
case表達式詳解