■예 4_1_19  ||  합계를 구함 - GROUP BY 와 ROLLUP
____SELECT DECODE(JOIN_GBN_CODE,NULL,'합계',JOIN_GBN_CODE) AS GBN_CODE,
COUNT(SABUN), MIN(ENG_NAME),
       COUNT(ENG_NAME), ROUND(AVG(SALARY))
FROM INSA
GROUP BY ROLLUP(JOIN_GBN_CODE);

■예 4_1_20  ||  소계를 구함 - GROUP BY 와 ROLLUP
SELECT DECODE(JOIN_GBN_CODE,NULL,'소계',JOIN_GBN_CODE) AS GBN_CODE,
SEX, COUNT(SABUN), MIN(ENG_NAME),
       COUNT(ENG_NAME), ROUND(AVG(SALARY))
FROM INSA
GROUP BY ROLLUP(JOIN_GBN_CODE), SEX;

■예 4_1_21  ||  소계와 합계를 함께 구함 - GROUP BY 와 ROLLUP
SELECT DECODE(JOIN_GBN_CODE,NULL,'합계',JOIN_GBN_CODE) AS GBN_CODE,
DECODE(SEX,NULL,DECODE(JOIN_GBN_CODE,NULL,' ','소계'),SEX) AS SEX,
COUNT(SABUN), MIN(ENG_NAME),
       COUNT(ENG_NAME), ROUND(AVG(SALARY))
FROM INSA
GROUP BY ROLLUP(JOIN_GBN_CODE,SEX);

■예 4_1_22  ||  합계를 구함 - GROUP BY 와 CUBE
SELECT DECODE(JOIN_GBN_CODE,NULL,'합계',JOIN_GBN_CODE) AS GBN_CODE,
COUNT(SABUN), MIN(ENG_NAME),
       COUNT(ENG_NAME), ROUND(AVG(SALARY))
FROM INSA
GROUP BY CUBE(JOIN_GBN_CODE);

■예 4_1_23  ||  소계를 구함 - GROUP BY 와 CUBE
SELECT DECODE(JOIN_GBN_CODE,NULL,'소계',JOIN_GBN_CODE) AS GBN_CODE,
SEX, COUNT(SABUN), MIN(ENG_NAME),
       COUNT(ENG_NAME), ROUND(AVG(SALARY))
FROM INSA
GROUP BY CUBE(JOIN_GBN_CODE), SEX;

■예 4_1_24  ||  소계와 합계를 함께 구함 - GROUP BY 와 CUBE
SELECT DECODE(JOIN_GBN_CODE,NULL,'합계',JOIN_GBN_CODE) AS GBN_CODE,
DECODE(SEX,NULL,DECODE(JOIN_GBN_CODE,NULL,' ','소계'),SEX) AS SEX,
COUNT(SABUN), MIN(ENG_NAME),
       COUNT(ENG_NAME), ROUND(AVG(SALARY))
FROM INSA
GROUP BY CUBE(JOIN_GBN_CODE,SEX);

■ 예 4_1_25  ||  합계를 구함 - GROUP BY 와 GROUPING SETS
SELECT DECODE(JOIN_GBN_CODE,NULL,'합계',JOIN_GBN_CODE) AS GBN_CODE,
COUNT(SABUN), MIN(ENG_NAME),
       COUNT(ENG_NAME), ROUND(AVG(SALARY))
FROM INSA
GROUP BY GROUPING SETS(JOIN_GBN_CODE,());

■예 4_1_26  ||  소계를 구함 - GROUP BY 와 GROUPING SETS
SELECT DECODE(JOIN_GBN_CODE,NULL,'소계',JOIN_GBN_CODE) AS GBN_CODE,
SEX, COUNT(SABUN), MIN(ENG_NAME),
       COUNT(ENG_NAME), ROUND(AVG(SALARY))
FROM INSA
GROUP BY GROUPING SETS((JOIN_GBN_CODE,SEX),(SEX));

■예 4_1_27  ||  소계와 합계를 함께 구함 - GROUP BY 와 GROUPING SETS
SELECT DECODE(JOIN_GBN_CODE,NULL,DECODE(SEX,NULL,'합계','소계'),JOIN_GBN_CODE)
AS GBN_CODE,
SEX, COUNT(SABUN), MIN(ENG_NAME),
       COUNT(ENG_NAME), ROUND(AVG(SALARY))
FROM INSA
GROUP BY GROUPING SETS((JOIN_GBN_CODE,SEX),(SEX),());

■예 4_1_28  ||  Nested Loop Join SQL문
SELECT /*+ ordered use_nl(t t1) */
        T.SABUN, T.ENG_NAME, T.JOIN_GBN_CODE, T.SALARY,
T1.CMP_NAME, T1.CMP_PHONE, T1.CMP_ADDR1
  FROM INSA T, INSA_COMPANY T1
  WHERE T.CMP_REG_NO = T1.CMP_REG_NO
  AND T.SABUN BETWEEN '2012121201' AND '2012123199'
  AND T1.CMP_REG_NO = '2222222206';

■예 4_1_29  ||  Sort Merge Join SQL문
SELECT /*+ LEADING(T1 T) USE_MERGE(T) */
        T.SABUN, T.ENG_NAME, T.JOIN_GBN_CODE, T.SALARY,
T1.CMP_NAME, T1.CMP_PHONE, T1.CMP_ADDR1
  FROM INSA T, INSA_COMPANY T1
WHERE T.CMP_REG_NO = T1.CMP_REG_NO;

■예 4_1_30  || Hash Join SQL문
SELECT T.SABUN, T.ENG_NAME, T.JOIN_GBN_CODE, T.SALARY,
T1.CMP_NAME, T1.CMP_PHONE, T1.CMP_ADDR1
  FROM____ INSA T, INSA_COMPANY T1
WHERE T.CMP_REG_NO = T1.CMP_REG_NO;