\uc694\uc57d.
1. \ud14c\uc774\ube14\uc5d0 \uc800\uc7a5\ub41c \ubaa8\ub4e0 \ub370\uc774\ud130\ub97c \ubcf4\uace0\uc790 \ud569\ub2c8\ub2e4. SELECT\uc640 FROM\uc808\ub85c \ub9cc\ub4e4\uc5b4 \ubcf4\ub77c.
-> SELECT \uce7c\ub7fc1, \uce7c\ub7fc2 FROM \ud14c\uc774\ube14<\/p>\n
2. \uc804\uccb4 \ub370\uc774\ud130 \uc911 \uc870\uac74\uc744 \ub9cc\uc871\ud558\ub294 \uac12\ub9cc \ubcf4\uace0 \uc2f6\uc2b5\ub2c8\ub2e4. WHERE \uc808\uc744 \uc774\uc6a9\ud574 \ubcf4\ub77c.
-> WHERE \uce7c\ub7fc \uc870\uac74 \uac12<\/p>\n
3. \uc77c\uc815\ud55c \uae30\ubd84\uc5d0 \uc758\ud574 \uc815\ub82c\ub418\uc5b4 \ud45c\ud604\ud558\uba74 \ubcf4\ub2e4 \uc27d\uac8c \uacb0\uacfc\ub97c \uc77d\uc5b4 \ub4e4\uc77c \uc218 \uc788\uc2b5\ub2c8\ub2e4. ORDER BY \uc808\uc744 \uc774\uc6a9\ud574 \ubcf4\ub77c.
-> ORDER BY \uce7c\ub7fc [ASC|DESC]<\/p>\n
4. \uc624\ub298 \uac00\uc7a5 \ub9ce\uc740 \ub9e4\ucd9c\uc561\uc744 \uc62c\ub9b0 \uc81c\ud488\uc774 \uad81\uae08\ud558\uc138\uc694? GROUP BY\uac00 \uc5ec\ub7ec\ubd84\uc5d0\uac8c \uadf8 \ub2f5\uc744 \uc81c\uc2dc\ud574 \uc904 \uac83\uc784.
-> GROUP BY<\/p>\n
5. GROUP BY \uc808\uc758 \uacb0\uacfc\ub85c\ubd80\ud130 \ud2b9\uc815 \uc870\uac74\uc744 \ub9cc\uc871\ud558\ub294 \uac12\uc744 \uc5bb\uace0\uc790 \ud55c\ub2e4\uba74 HAVING \uc808\uc744 \uc0ac\uc6a9\ud558\ub77c.
-> HAVING \uce7c\ub7fc \uc5f0\uc0b0\uc790 \uac12<\/p>\n
====================================================<\/p>\n
SQL\uc740 \uc5ec\ub7ec\ubd84\uc774 \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc640 \uc774\uc57c\uae30\ud560 \uc218 \uc788\ub294 \uc5b8\uc5b4\uc785\ub2c8\ub2e4. \uc5ec\ub7ec\ubd84\uc774 \ud55c\uad6d\uc5b4\ub97c \ud1b5\ud574 \uc0ac\ub78c\ub4e4\uacfc \uc758\uc0ac \ud45c\ud604\uc744 \uc8fc\uace0 \ubc1b\ub4ef\uc774 \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc5d0 \uc800\uc7a5\ub41c \ub370\uc774\ud130\ub97c \ucc98\ub9ac\ud558\uae30 \uc704\ud574\uc11c\ub3c4 \uc5b8\uc5b4\uac00 \ud544\uc694\ud558\uc9c0\uc694. \uc989 \ub370\uc774\ud130\ubca0\uc774\uc2a4\uc640\uc758 \uc18c\ud1b5\uc744 \uc704\ud574 \uc5ec\ub7ec\ubd84\uc774 \uc54c\uc544\ub450\uc5b4\uc57c \ud558\ub294 \uc5b8\uc5b4\uac00 \ubc14\ub85c SQL(Structured Query Language)\uc785\ub2c8\ub2e4.<\/p>\n
====================================================<\/p>\n
2.1 \ub0b4 \ub9d8\ub300\ub85c \ub370\uc774\ud130 \uc5bb\uae30 – SELECT<\/p>\n
1) SELECT\ub97c \uc774\uc6a9\ud55c \ub370\uc774\ud130 \uc870\ud68c
-> \ud14c\uc774\ube14\uc758 \ub370\uc774\ud130\ub97c \uc870\ud68c\ud558\ub294 \uae30\ubcf8\uc801\uc778 SQL\ubb38\uc740 \ub2e4\uc74c\uacfc \uac19\ub2e4.<\/p>\n
SELECT \uce7c\ub7fc \uc774\ub9841, \uce7c\ub7fc \uc774\ub9842
FROM \ud14c\uc774\ube14 \uc774\ub984;<\/p>\n
\uac04\ub2e8\ud55c SQL\ubb38\uc740 \uc704\uc640 \uac19\uc774 SELECT\uc640 FROM\uc808\ub85c \uad6c\uc131\ub418\uc5b4 \uc788\uc2b5\ub2c8\ub2e4. SELECT\uc808 \ub2e4\uc74c\uc5d0\ub294 \uce7c\ub7fc \uc774\ub984\uc774 \uc624\uba70, FROM\uc808 \ub2e4\uc74c\uc5d0\ub294 \ud14c\uc774\ube14\uc758 \uc774\ub984\uc774 \uc628\ub2e4.<\/p>\n
2) \ud2b9\uc815 \uce7c\ub7fc \uc120\ud0dd
-> \ud2b9\uc815 \uce7c\ub7fc\uc744 \uc120\ud0dd\ud558\uace0\uc790 \ud55c\ub2e4\uba74 SELECT\uc808\uc5d0 \uc544\ub798\uc640 \uac19\uc774 \uce7c\ub7fc\uc744 \uc9c0\uc815\ud574 \ub450\uba74 \ub429\ub2c8\ub2e4. \uccab \ubc88\uc9f8 \uceec\ub984\uc740 employee_id(\uc0ac\uc6d0\ubc88\ud638)\uc774\uba70, \ub450 \ubc88\uc9f8 \uce7c\ub7fc\uc740 last_name(\uc0ac\uc6d0\uc758 \uc774\ub984)\uc785\ub2c8\ub2e4.<\/p>\n
SQL> SELECT employee_id, last_name
2 FROM employees;<\/p>\n
\uc774\uc0c1\uc5d0\uc11c SELECT\ubb38\uc740 SELECT \uba85\ub839\uc73c\ub85c \uc2dc\uc791\ud574\uc11c ;(\uc138\ubbf8\ucf5c\ub860)\uc73c\ub85c \uc885\ub8cc\ud558\uba70, SELECT\uc808\uacfc FROM\uc808\ub85c \uad6c\uc131\ub428\uc744 \uc54c \uc218 \uc788\uc2b5\ub2c8\ub2e4.
\uadf8\ub7ec\ub098 \uc9c8\uc758 \uac00 \ud14c\uc774\ube14\uc5d0 \uc800\uc7a5\ub41c \uc804\uccb4 \ub370\uc774\ud130\ub97c \ubaa8\ub450 \ubcf4\uc5ec\uc900\ub2e4\uba74 \uc694\uc998\uacfc \uac19\uc740 \ub300\uc6a9\ub7c9\uc758 \ub370\uc774\ud130\ub97c \uc800\uc7a5\ud558\ub294 \ud14c\uc774\ube14\uc5d0\uc11c\ub294 \uc758\ubbf8 \uc5c6\ub294 \uc9c8\uc758\uac00 \ub420 \uac83\uc785\ub2c8\ub2e4. \ub300\uc6a9\ub7c9\uc758 \ub370\uc774\ud130\uac00 \ud654\uba74\uc5d0 \ucd9c\ub825\ub418\ub294 \ubaa8\uc2b5\ub9cc\uc744 \ubcf4\uac8c \ub418\uae30 \ub54c\ubb38\uc785\ub2c8\ub2e4.<\/p>\n
====================================================<\/p>\n
2.2 WHERE\uc808<\/p>\n
1) WHERE\uc808\uc758 \uae30\ubcf8
-> WHERE\uc808\uc740 \uc804\uccb4 \ub370\uc774\ud130 \uc911 \uc870\uac74\uc744 \ub9cc\uc871\ud558\ub294 \uac12\ub9cc \uc5bb\uc744 \uc218 \uc788\ub3c4\ub85d \ud569\ub2c8\ub2e4. WHERE\uc808\uc740 \ub2e4\uc74c\uacfc \uac19\uc774 \uc774\ub8e8\uc5b4 \uc9d1\ub2c8\ub2e4.<\/p>\n
WHERE \uce7c\ub7fc\uc774\ub984 \uc870\uac74 \uac12<\/p>\n
\uadf8\ub807\ub2e4\uba74, \uc55e\uc758 \uc0ac\uc6d0 \ud14c\uc774\ube14\uc5d0\uc11c \uc774\ub984\uc774 King\uc778 \uc0ac\uc6d0\uc758 \uc0ac\uc6d0\ubc88\ud638\uc640 \uc785\uc0ac\uc77c \uc815\ubcf4\ub97c \uc5bb\uc5b4\ubcf4\ub3c4\ub85d \ud558\uc8e0.<\/p>\n
SQL> SELECT employee_id, hire_date
2 FROM employees
3 WHERE last_name=’King’;<\/p>\n
EMPLOYEE_ID HIRE_DATE
———– ———
156 30-JAN-96
100 17-JUN-87<\/p>\n
WHERE\uc808\uc744 \ubcf4\uba74 last_name \uce7c\ub7fc\uc758 \uac12\uc774 ‘King’\uacfc \uc77c\uce58\ud558\ub294 \ud589\uc744 \ucc3e\uc2b5\ub2c8\ub2e4. \uc870\uac74\uc744 \ub9cc\uc871\ud558\ub294 \ud589\ub4e4 \uc911\uc5d0\uc11c \uc0ac\uc6d0\ubc88\ud638(employee_id)\uc640 \uc785\uc0ac\uc77c(hire_date)\uce7c\ub7fc\uc5d0 \ub300\ud55c \uac12\uc744 \ubc18\ud658\ud569\ub2c8\ub2e4. \uc5ec\uae30\uc11c \uc8fc\uc758\ud560 \uc810\uc740 \ud14c\uc774\ube14\uc5d0 \uc800\uc7a5\ub41c \ubb38\uc790 \ub370\uc774\ud130\uc5d0 \ub300\ud574\uc11c\ub294 \ub300\uc18c\ubb38\uc790\ub97c \uad6c\ubd84\ud55c\ub2e4\ub294 \uac83, \uadf8\ub9ac\uace0 \ubb38\uc790, \ub0a0\uc9dc \ub370\uc774\ud130\ub294 ‘ (single quotation)\uc73c\ub85c \ubb36\uc5b4\uc11c \ud45c\ud604\ud574 \uc8fc\uc5b4\uc57c \ud55c\ub2e4\ub294 \uac83\uc785\ub2c8\ub2e4.<\/p>\n
SQL> SELECT employee_id, hire_date
2 FROM employees
3 WHERE last_name = ‘king’;<\/p>\n
no rows selected<\/p>\n
2) AND\ub97c \uc774\uc6a9\ud55c \uc870\uac74\uc808 \uc791\uc131
-> \uc804\uccb4 \uc0ac\uc6d0 \uc911 \uae09\uc5ec\uac00 $10,000 \uc774\uc0c1 $20,000 \uc774\ud558\uc778 \uc0ac\uc6d0\ub4e4\uc744 \uc5bb\uc5b4\ubcf4\ub294 \uc608\uc81c\uc785\ub2c8\ub2e4. \uc774 \uacbd\uc6b0 \ubb38\uc81c\ub97c \ub2e4\uc2dc \ud574\uc11d\ud558\uba74, \uc0ac\uc6d0\uc758 \uae09\uc5ec\ub294 $10,000 \uc774\uc0c1\uc774\uba74\uc11c, $20,000 \uc774\ud558\uc778 \uc870\uac74\uc744 \ubaa8\ub450 \ub9cc\uc871\ud574\uc57c \ud569\ub2c8\ub2e4. \uc774 \uacbd\uc6b0 \ub17c\ub9ac \uc5f0\uc0b0\uc790 AND\ub97c \uc0ac\uc6a9\ud574\uc11c \ub098\ud0c0\ub0bc \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
SQL> SELECT employee_id, last_name, salary
2 FROM employees
3 WHERE salary >= 10000
4 AND salary <= 20000;<\/p>\n
3) OR\ub97c \uc774\uc6a9\ud55c \uc870\uac74\uc808 \uc791\uc131
-> \uadf8\ub807\ub2e4\uba74, \uc0ac\uc6d0\uac00 \uc9c1\ubb34\uac00 ‘FI_MGR’\uacfc ‘FI_ACCOUNT’\uc778 \uc0ac\uc6d0\ub4e4\uc758 \ubaa9\ub85d\uc744 \uc5bb\uc73c\ub824\uba74 \uc5b4\ub5bb\uac8c \ud574\uc57c \ud560\uae4c\uc694. \uc989 \uc0ac\uc6d0\uc758 \uc9c1\ubb34\uac00 ‘FI_MGR’\uacfc ‘FI_ACCOUNT’\uc911 \ud558\ub098\ub77c\ub3c4 \ub9cc\uc871\ud558\ub294 \uc0ac\uc6d0\ub4e4\uc744 \ubaa8\ub450 \ud3ec\ud568\ud558\ub294 \uacb0\uacfc\ub97c \uc608\uc0c1\ud560 \uc218 \uc788\uaca0\uc9c0\uc694.<\/p>\n
SQL> SELECT employee_id, last_name, salary
2 FROM employees
3 WHERE job_id = ‘FI_MGR’
4 OR job_id = ‘FI_ACCOUNT’;<\/p>\n
EMPLOYEE_ID LAST_NAME SALARY
———– ————————- ———-
109 Faviet 9000
110 Chen 8200
111 Sciarra 7700
112 Urman 7800
113 Popp 6900
108 Greenberg 12000<\/p>\n
6 rows selected.<\/p>\n
4) BETWEEN AND\ub97c \uc774\uc6a9\ud55c \uc870\uac74\uc808 \uc791\uc131
-> \ubc94\uc704\ub97c \uc9c0\uc815\ud560 \ub54c\ub294 BETWEEN AND \uc870\uac74\uc744 \uad8c\uc7a5\ud569\ub2c8\ub2e4. \ubcf4\ub2e4 \uac04\uacb0\ud558\uac8c \ud45c\ud604\ub418\uae30 \ub54c\ubb38\uc785\ub2c8\ub2e4. \uc774\ub294 \ubcf5\uc7a1\ud55c \uc9c8\uc758\ubb38\uc5d0\uc11c WHERE \uc870\uac74\uc808\uc744 \ubcf4\ub2e4 \ubd84\uba85\ud788 \ub098\ud0c0\ub0bc \uc218 \uc788\ub294 \uc7a5\uc810\uc774 \uc788\uc2b5\ub2c8\ub2e4. \uadf8\ub7ec\ub098 $10,000\uc744 \ucd08\uacfc\ud558\uac70\ub098 $20,000 \ubbf8\ub9cc\uc77c \ub54c\ub294 > (\ud06c\uac70\ub098), < (\uc791\uc740) \uc640 \uac19\uc774 \ube44\uad50\ud574\uc57c\uaca0\uc9c0\uc694.<\/p>\n
SQL> SELECT employee_id, last_name, salary
2 FROM employees
3 WHERE salary BETWEEN 10000 AND 20000;<\/p>\n
5) IN\uc744 \uc774\uc6a9\ud55c \uc870\uac74\uc808 \uc791\uc131
-> \ub9cc\uc57d \uc6d0\ud558\ub294 \uc9c1\ubb34\uac00 \ub354 \ucd94\uac00\ub418\ub294 \uacbd\uc6b0\ub294?<\/p>\n
SQL> SELECT employee_id, last_name, job_id
2 FROM employees
3 WHERE job_id = ‘FI_MGR’
4 OR job_id = ‘FI_ACCOUNT’
5 OR job_id = ‘SA_MGR’
6 OR job_id = ‘SA_REP’;<\/p>\n
\uc774 \uacbd\uc6b0 IN \uc870\uac74\uc744 \ud1b5\ud574 SQL \ubb38\uc7a5\uc744 \uac04\uacb0\ud558\uac8c \ub098\ud0c0\ub0bc \uc218 \uc788\ub2e4.<\/p>\n
SQL> SELECT employee_id, last_name, job_id
2 FROM employees
3 WHERE job_id IN (‘FI_MGR’, ‘FI_ACCOUNT’, ‘SA_MGR’, ‘SA_REP’);<\/p>\n
6) IS NULL\/NOT \uc744 \uc774\uc6a9\ud55c \uc870\uac74\uc808 \uc791\uc131
-> \uc9c8\uc758\ubb38\uc774 \uc870\uac74\uc744 \ub9cc\uc871\ud558\ub294 \uacb0\uacfc\ub97c \uc791\uc131\ud574 \ubcf4\uc558\ub294\ub370 \uadf8\ub807\uc9c0 \uc54a\uc740 \uacbd\uc6b0\ub3c4 \uc0dd\uac01\ud574 \ubcfc \uc218 \uc788\uc744 \uac83\uc774\ub2e4. <\/p>\n
SQL> SELECT employee_id, last_name, salary, commission_pct
2 FROM employees
3 WHERE commission_pct IS NOT NULL;<\/p>\n
NULL\uc774 \ud560\ub2f9\ub418\uc9c0 \uc54a\uc740 \uac12\uc774\ubbc0\ub85c \uc774\uc5d0 \ub300\ud55c \ubd80\uc815\uc73c\ub85c NULL \uc55e\uc5d0 NOT\uc744 \ubd99\uc5ec \uc0ac\uc6a9\ud558\uba74 \ub41c\ub2e4. \ubd80\uc815\uc740 \uc774\uc640 \uac19\uc774 \uc870\uac74\uc758 \uc55e\uc5d0 \ubd99\uc5ec \uc0ac\uc6a9\ud560 \uc218 \uc788\ub294\ub370, NOT BETWEEN AND\ub098 NOT IN\uacfc \uac19\uc774 \uc0ac\uc6a9\ud558\uba70, \uc218\uc2dd\uc5d0\uc11c\ub294 ‘!=’ (\uac19\uc9c0\uc54a\uc74c)\uc758 \uc758\ubbf8\uac00 \uc788\ub2e4.<\/p>\n
7) LIKE\ub97c \uc774\uc6a9\ud55c \uc870\uac74\uc808 \uc791\uc131
-> 1997\ub144\uc5d0 \uc785\uc0ac\ud55c \uc0ac\uc6d0\ub4e4\uc758 \ub9ac\uc2a4\ud2b8 \uc5bb\uae30.<\/p>\n
SQL> SELECT employee_id, last_name, hire_date
2 FROM employees
3 WHERE hire_date BETWEEN ’01\/Feb\/97′ AND ’31\/Dec\/97′;<\/p>\n
\uc774 \uc9c8\uc758\ubb38\uc740 \ub2e4\uc74c\uacfc \uac19\uc774 \uc791\uc131\ub420 \uc218\ub3c4 \uc788\ub2e4.<\/p>\n
SQL> SELECT employee_id, last_name, hire_date
2 FROM employees
3 WHERE hire_date LIKE ‘%97’;<\/p>\n
‘%97’ \uc758 \uc758\ubbf8\ub294 97\ub85c \ub05d\ub098\ub294 \ubaa8\ub4e0 \uac12\uc740 \uc870\uac74\uc744 \ub9cc\uc871\ud568\uc744 \ub098\ud0c0\ub0b4\uba70, LIKE \uc870\uac74\uacfc \ud568\uaed8 \uc0ac\uc6a9\ub41c\ub2e4. \ud639 \uc5ec\ub7ec\ubd84\uc774 \uc800\uc7a5\ub41c \uac12\uc758 \uc77c\ubd80\ub9cc\uc744 \uae30\uc5b5\ud558\uace0 \uc788\uc744 \ub54c\uc5d0\ub3c4 LIKE\ub294 \uc720\uc6a9\ud558\uac8c \uc0ac\uc6a9\ud560 \uc218 \uc788\ub2e4.<\/p>\n
LIKE \uc808\uc5d0\uc11c \uc0ac\uc6a9\ud560 \uc218 \uc788\ub294 \uc640\uc77c\ub4dc \uce74\ub4dc \ubc0f ESCAPE \uc635\uc158
-> \uc55e\uc5d0\uc11c \uc0ac\uc6a9\ud55c ‘%’\ub294 0~n \uac1c\uc758 \ubb38\uc790\uc5f4\uc744 \ub300\uccb4\ud55c\ub2e4. \uc774\uc678\uc5d0\ub3c4 \ub2e8 \ud558\ub098\uc758 \uae00\uc790\ub9cc\uc744 \ub300\uccb4\ud558\ub294 ‘_’ \uc640\uc77c\ub4dc \uce74\ub4dc\ub3c4 \uc788\ub2e4.
\uadf8\ub7ec\uba74 %\ub098 _\uac00 \ud3ec\ud568\ub41c \ubb38\uc790\uc5f4\uc744 \uac80\uc0c9\ud558\uace0\uc790 \ud560 \ub54c\ub294 \uc5b4\ub5bb\uac8c \ud574\uc57c \ud560\uae4c. \uc774\ub54c\ub294 ESCAPE \uc635\uc158\uc744 \uc0ac\uc6a9\ud558\uc5ec ESCAPE \ubb38\uc790\ub97c \uc9c0\uc815\ud55c \ud6c4 ESCAPE \ubb38\uc790\ub97c \uc774\uc6a9\ud558\uc5ec %\ub098 _\ub97c \uc640\uc77c\ub4dc \uce74\ub4dc\uac00 \uc544\ub2cc \ud558\ub098\uc758 \ubb38\uc790\ub97c \uc778\uc2dd\ud558\ub3c4\ub85d \ud560 \uc218 \uc788\ub2e4. \ub2e4\uc74c\uc740 last_name\uc5d0 ‘Au%’\ub85c \uc2dc\uc791\ud558\ub294 \ubb38\uc790\uc5f4\uc744 \uac80\uc0c9\ud558\ub294 \uc608\uc81c\uc774\ub2e4.<\/p>\n
SQL> SELECT employee_id, last_name
2 FROM employees
3 WHERE last_name LIKE ‘Au%%’ ESCAPE ”;<\/p>\n
\ucc38\uace0\ub85c \uc5f0\ub3c4\ub97c \uc774\uc6a9\ud558\uc5ec \uc870\uac74\uc744 \ub9cc\uc871\ud558\ub294 \uac12\uc744 \ucc3e\uc744 \ub54c\ub294 \uc815\ud655\ud788 4\uc790\ub9ac\ub85c \ud45c\ud604\ud558\ub294 \uac83\uc774 \ubc14\ub78c\uc9c1\ud558\ub2e4. \uc55e\uc11c \uc5f0\ub3c4 4\uc790\ub9ac \uc911 \ub4a4 2\uc790\ub9ac\ub9cc \ub098\ud0c0\ub0b8\ub2e4\uba74 1990\ub144\uacfc 2090\ub144\uc758 \uad6c\ubd84\uc774 \uc758\ubbf8\uac00 \uc5c6\uc5b4\uc9c0\uae30 \ub54c\ubb38\uc774\ub2e4.<\/p>\n
\uc544\ub798\uc758 \uc9c8\uc758\ubb38\uc740 \ud568\uc218\ub97c \uc774\uc6a9\ud558\uc5ec \ub354\uc6b1 \uba85\ud655\ud55c \uc9c8\uc758\ubb38\uc744 \uc791\uc131\ud574 \ubcf8 \uc608\uc774\ub2e4.<\/p>\n
SQL> SELECT employee_id, last_name, hire_date
2 FROM employees
3 WHERE TO_CHAR(hire_date, ‘YYYY’) = ‘1997’;<\/p>\n
8) \uc5f0\uc0b0\uc790 \uc815\ub9ac
= : \ub3d9\uc77c\ud568(\uac19\uc74c)\uc744 \ud14c\uc2a4\ud2b8\ud55c\ub2e4.<\/p>\n
!=, <>, ^= : \ub3d9\uc77c\ud558\uc9c0 \uc54a\uc74c(\uac19\uc9c0 \uc54a\uc74c)\uc744 \ud14c\uc2a4\ud2b8\ud55c\ub2e4.<\/p>\n
>=, >, <=, < : \ud070 \uacbd\uc6b0 \ud639\uc740 \ud06c\uac70\ub098 \uac19\uc740 \uacbd\uc6b0\uc758 \ube44\uad50 \ud14c\uc2a4\ud2b8\ub97c \ud55c\ub2e4. \uc774\uc640 \ubc18\ub300\uc758 \uacbd\uc6b0\ub3c4 \uc801\uc6a9\ub41c\ub2e4.<\/p>\n
AND : ‘A AND B’\uc758 \uacbd\uc6b0 \ub450 \uc870\uac74 \ubaa8\ub450\ub97c \ub9cc\uc871\ud574\uc57c \ud55c\ub2e4.<\/p>\n
OR : ‘A OR B’\uc758 \uacbd\uc6b0 \ub450 \uc870\uac74 \uc911 \ud558\ub098\ub97c \ub9cc\uc871\ud558\ub294 \uacbd\uc6b0\uc774\ub2e4.<\/p>\n
BETWEEN AND : \uc8fc\uc5b4\uc9c4 \ubc94\uc704\uc758 \uac12\uc5d0 \ud574\ub2f9\ud558\uba74 \uadf8 \uac12\uc744 \ubc18\ud658\ud55c\ub2e4.<\/p>\n
IN : \ud558\ub098 \uc774\uc0c1\uc758 \ub3d9\uc77c \uc870\uac74\uc744 \ub9cc\uc871\ud574\uc57c \ud558\ub294 \uacbd\uc6b0\uc774\ub2e4.<\/p>\n
LIKE : \uc870\uac74\uc758 \uc77c\ubd80\uc640 \uc77c\uce58\ud558\ub294 \uacbd\uc6b0\uc5d0 \uc801\uc6a9\ub41c\ub2e4.<\/p>\n
IS NULL \/ IS NOT NULL : \ud560\ub2f9\ub418\uc9c0 \uc54a\uc740 \uac12\uc744 \ub9cc\uc871\ud558\ub294 \uacbd\uc6b0\uc774\ub2e4. \ud560\ub2f9\ub41c \uac12\uc758 \uacbd\uc6b0 NULL \uc55e\uc5d0 NOT\uc744 \uc0ac\uc6a9\ud55c\ub2e4.<\/p>\n
====================================================<\/p>\n
2.3 ORDER BY<\/p>\n
1) ORDER BY ASC
-> \ub54c\ub85c\ub294 \ub370\uc774\ud130\ub97c \uc77c\uc815\ud55c \uae30\uc900\uc5d0 \uc758\ud558\uc5ec \uc815\ub82c\ud558\uc5ec \ud45c\ud604\ud558\uba74 \ub354\uc6b1 \uc27d\uac8c \uacb0\uacfc\ub97c \uc77d\uc5b4\ub4e4\uc77c \uc218 \uc788\ub294\ub370 ORDER BY \uc808\uc744 \uc774\uc6a9\ud558\uba74 \uac00\ub2a5\ud558\ub2e4.<\/p>\n
ORDER BY \uce7c\ub7fc\uc774\ub984 [ASC\/DESC]<\/p>\n
\uce7c\ub7fc \uc774\ub984 \ub4a4 \ub300\uad04\ud638([ ])\ub294 \uc120\ud0dd\uc0ac\ud56d\uc774\uba70, \uae30\ubcf8\uc740 \uc624\ub984\ucc28\uc21c \uc815\ub82c\uc778 ‘ASC’\uc774\ub2e4. ‘ASC’\ub294 ‘Ascend(\uc62c\ub77c\uac00\ub2e4)’\uc758 \uc57d\uc790\uc774\ubbc0\ub85c, \uc791\uc740 \uac12\ubd80\ud130 \ud070 \uac12\uc758 \uc21c\uc11c\ub85c \uc815\ub82c\ub41c \uacb0\uacfc\ub97c \ubcf4\uc5ec\uc900\ub2e4. \ucc38\uace0\ub85c ‘DESC’\ub294 ‘Descend(\ub0b4\ub824\uac00\ub2e4)’\uc758 \uc57d\uc790\uc774\ub2e4.<\/p>\n
SQL> SELECT employee_id, last_name, salary
2 FROM employees
3 WHERE salary >= 10000
4 ORDER BY salary;<\/p>\n
ORDER BY\ub294 WHERE \uc870\uac74\uc808\uc744 \ub9cc\uc871\ud558\ub294 \uacb0\uacfc\ub85c\ubd80\ud130 \ud2b9\uc815 \uce7c\ub7fc\uc758 \uac12\uc744 \uae30\uc900\uc73c\ub85c \uc815\ub82c\ud55c \uacb0\uacfc\ub97c \ubcf4\ub0b4\uc900\ub2e4. WHERE \uc870\uac74\uc744 \ub9cc\uc871\ud558\ub294 \uacb0\uacfc\ub97c \uba3c\uc800 \uc5bb\uc740 \ud6c4, \uadf8 \uacb0\uacfc\ub85c\ubd80\ud130 \ud2b9\uc815 \uce7c\ub7fc(salary)\uc744 \uae30\uc900\uc73c\ub85c \uc815\ub82c\ud558\uc5ec \ucd5c\uc885 \uacb0\uacfc\ub97c \ubcf4\uc5ec\uc900\ub2e4.<\/p>\n
2) ORDER BY DESC<\/p>\n
SQL> SELECT employee_id, last_name, hire_date
2 FROM employees
3 WHERE hire_date >= ’01\/Jan\/00′
4 ORDER BY hire_date DESC;<\/p>\n
EMPLOYEE_ID LAST_NAME HIRE_DATE
———– ————————- ———
173 Kumar 21-APR-00
167 Banda 21-APR-00
166 Ande 24-MAR-00
128 Markle 08-MAR-00
165 Lee 23-FEB-00
136 Philtanker 06-FEB-00
183 Geoni 03-FEB-00
149 Zlotkey 29-JAN-00
164 Marvins 24-JAN-00
199 Grant 13-JAN-00
179 Johnson 04-JAN-00<\/p>\n
11 rows selected.<\/p>\n
\ub0b4\ub9bc\ucc28\uc21c\uc740 DESC(Descending) \ud0a4\uc6cc\ub4dc\ub97c \uba85\uc2dc\uc801\uc73c\ub85c ORDER BY \uc808\uc5d0\uc11c \ub098\ud0c0\ub0b4 \uc8fc\uc5b4\uc57c \ud55c\ub2e4. <\/p>\n
====================================================<\/p>\n
2.4 GROUP BY<\/p>\n
1) GROUP BY\ub97c \uc774\uc6a9\ud55c \uadf8\ub8f9\ud654
-> SQL\uc5d0\uc11c\ub294 GROUP BY \uc808\uacfc \uc9d1\ud569 \ud568\uc218\ub97c \uc774\uc6a9\ud568\uc73c\ub85c\uc368 \ub370\uc774\ud130\ub97c \ud65c\uc6a9\ud560 \uc218 \uc788\ub2e4. GROUP BY \uc808\uc740 \uc77c\ubc18\uc801\uc73c\ub85c \uc9c8\uc758\ubb38\uc73c\ub85c\ubd80\ud130 \uc5bb\uc740 \uacb0\uacfc\uc5d0 \ub300\ud574 GROUP BY \uc808\uc5d0 \uba85\uc2dc\ud55c \uce7c\ub7fc\uc758 \uac12\uc774 \uac19\uc744 \ub54c \uadf8\ub8f9\uc744 \ub9cc\ub4e4\uace0, \uc774 \uadf8\ub8f9\uc73c\ub85c\ubd80\ud130 SQL \ud45c\uc900 \ud568\uc218\uc778 \uc9d1\ud569 \ud568\uc218\ub97c \ud1b5\ud574 \ub2e4\uc591\ud55c \uacb0\uacfc\ub97c \uc5bb\ub294\ub2e4.<\/p>\n
SQL> SELECT AVG(salary)
2 FROM employees;<\/p>\n
AVG(SALARY)
———–
6461.68224<\/p>\n
\ub300\ub7b5 $6,462 \uc815\ub3c4\ub97c \uc5bb\uc744 \uc218 \uc788\ub2e4. AVG() \ud568\uc218\ub294 \ud558\ub098 \uc774\uc0c1\uc758 \uac12\ub4e4\ub85c\ubd80\ud130 \ud3c9\uade0\uac12\uc744 \ubc18\ud658\ud55c\ub2e4. \uadf8\ub807\ub2e4\uba74 $10,000 \uc774\uc0c1\uc758 \uc5f0\ubd09\uc790\ub4e4\uc758 \ud3c9\uade0\uc740 \uc5bc\ub9c8\uc77c\uae4c<\/p>\n
SQL> SELECT AVG(salary)
2 FROM employees
3 WHERE salary >= 10000;<\/p>\n
AVG(SALARY)
———–
12631.5789<\/p>\n
\uc774 \uacbd\uc6b0\ub294 WHERE\uc808\uc744 \ub9cc\uc871\ud558\ub294 \ud589\uc758 \uacb0\uacfc\ub97c \ud558\ub098\uc758 \uadf8\ub8f9\uc73c\ub85c \ubcf4\uace0 \ud3c9\uade0\uc744 \uc5bb\uc740 \uacbd\uc6b0\uc774\ub2e4.<\/p>\n
\uadf8\ub807\ub2e4\uba74, \ubd80\uc11c\ubcc4 \uae09\uc5ec\uc758 \ud3c9\uade0\uc744 \uc5bb\uc5b4\ubcf4\uc790. \ubd80\uc11c\ubcc4 \ud3c9\uade0\uc740 \uac01\uac01\uc758 \ubd80\uc11c\ub9c8\ub2e4 \ud3c9\uade0\uc744 \uc5bb\uc5b4\uc57c \ud558\ubbc0\ub85c \uac19\uc740 \ubd80\uc11c \ub2e8\uc704\ub85c \uadf8\ub8f9\uc744 \ubb36\uc5b4 \ud3c9\uade0\uc744 \uc5bb\ub294\ub2e4.<\/p>\n
SQL> SELECT department_id, AVG(salary)
2 FROM employees
3 GROUP BY department_id
4 ORDER BY department_id;<\/p>\n
DEPARTMENT_ID AVG(SALARY)
————- ———–
10 4400
20 9500
30 4150
40 6500
50 3475.55556
60 5760
70 10000
80 8955.88235
90 19333.3333
100 8600
110 10150<\/p>\n
DEPARTMENT_ID AVG(SALARY)
————- ———–
7000<\/p>\n
12 rows selected.<\/p>\n
\uacb0\uacfc\ub97c \ubcf4\uba74 \ubd80\uc11c \uc544\uc774\ub514\uac00 \uc624\ub984\ucc28\uc21c \uc815\ub82c\ub418\uc5b4 \ubd80\uc11c\ub9c8\ub2e4 \ud574\ub2f9 \ubd80\uc11c\uc5d0 \uc18d\ud55c \uc0ac\uc6d0\uc758 \ud3c9\uade0 \uae09\uc5ec\ub97c \uc5bb\uc5b4\ub0b4\uace0 \uc788\ub2e4. \ucc38\uace0\ub85c NULL \uac12(\ud560\ub2f9\ub418\uc9c0 \uc54a\uc740 \uac12)\uc740 \uc624\ub984\ucc28\uc21c \uc815\ub82c\ud560 \ub54c \uc704\uc640 \uac19\uc774 \uac00\uc7a5 \ub098\uc911\uc5d0 \ub098\ud0c0\ub09c\ub2e4.<\/p>\n
\ub2e4\uc74c\uc758 \uc870\uac74\uc744 \ub9cc\uc871\ud558\ub294 \uc9c8\uc758\ubb38\uc744 \uc791\uc131\ud574 \ubcf4\ub77c.
\uc694\uad6c\uc0ac\ud56d – \uc9c1\ubb34\ubcc4\ub85c \ucd5c\ub300 \uae09\uc5ec\uc640 \ucd5c\uc18c \uae09\uc5ec\ub97c \uc0b4\ud3b4 \ubcf4\uace0\uc790 \ud55c\ub2e4. \ub2e8 \uc9c1\ubb34\ub294 \uc601\uc5c5 \ubd80\uc11c\ub85c \uc81c\ud55c\ud55c\ub2e4.<\/p>\n
\uba3c\uc800 \uc0ac\uc6d0 \ud14c\uc774\ube14\uc5d0\uc11c \uace0\ub824\ud574\uc57c \ud560 \uce7c\ub7fc\uc774 \ubb34\uc5c7\uc778\uc9c0 \uc0b4\ud3b4\ubcf4\uc544\uc57c \ud55c\ub2e4. \uadf8\ub9ac\uace0 \uc601\uc5c5 \ubd80\uc11c\ub294 \uc5b4\ub5bb\uac8c \ud45c\ud604\ub418\uace0 \uc788\ub294\uc9c0 \uc0b4\ud3b4\ubcf4\uc544\uc57c \ud55c\ub2e4. \uc601\uc5c5 \ubd80\uc11c\ub294 \ub2e4\uc2dc \uc601\uc5c5 \ub300\ud45c(SA_REP)\uc640 \uc774\ub4e4\uc758 \uad00\ub9ac\uc790\uc778 \uc601\uc5c5 \uad00\ub9ac\uc790(SA_MIN)\uac00 \uc788\ub2e4.<\/p>\n
\uadf8\ub7fc \uc6b0\uc120 \ub300\uc0c1\uc774 \ub418\ub294 \uc9c8\uc758\ubb38\uc744 \uc791\uc131\ud55c\ub2e4.<\/p>\n
SQL> SELECT job_id, salary
2 FROM employees;<\/p>\n
\uc774 \uacb0\ub85c\ubd80\ud130 \uba3c\uc800 \ubd80\uc11c\ub97c \uc81c\ud55c\ud55c\ub2e4.<\/p>\n
SQL> SELECT job_id, salary
2 FROM employees
3 WHERE job_id IN(‘SA_REP’, ‘SA_MAN’);<\/p>\n
\ub9c8\uc9c0\ub9c9\uc73c\ub85c \uc704 \uacb0\ub85c\ubd80\ud130 \uae09\uc5ec\uc758 \ucd5c\ub300\uac12\/\ucd5c\uc18c\uac12\uc744 \uc5bb\ub294\ub2e4. \ud558\ub098 \uc774\uc0c1\uc758 \ud589\uc73c\ub85c\ubd80\ud130 \ucd5c\ub300\uac12\/\ucd5c\uc18c\uac12\uc744 \ubc18\ud658\ud558\ub294 MAX() \/ MIN() \ud568\uc218\ub97c \uc0ac\uc6a9\ud55c\ub2e4.<\/p>\n
SQL> SELECT job_id, MAX(salary), MIN(salary)
2 FROM employees
3 WHERE job_id IN(‘SA_REP’, ‘SA_MAN’)
4 GROUP BY job_id;<\/p>\n
JOB_ID MAX(SALARY) MIN(SALARY)
———- ———– ———–
SA_MAN 14000 10500
SA_REP 11500 6100<\/p>\n
2) GROUP BY \uc751\uc6a9
-> \uc5f0\ub3c4\ubcc4 \uc785\uc790\ub4e4\uc758 \ud3c9\uade0\uc740 \uc5bc\ub9c8\uc778\uc9c0 \ub098\ud0c0\ub0b4 \ubcf4\ub77c.<\/p>\n
SQL> SELECT hire_date, salary
2 FROM employees;<\/p>\n
\uc785\uc0ac\uc77c(hire_date)\uc744 \uc5f0\ub3c4\ub85c \ubcc0\ud658\ud55c \ud6c4 GROUP BY\ub97c \uc774\uc6a9\ud558\uc5ec \uadf8\ub8f9\ud654\ud55c\ub2e4. TO_CHAR() \ud568\uc218\ub97c \uc0ac\uc6a9\ud558\uba74 \ub0a0\uc9dc \ud615\uc2dd\uc758 \ub370\uc774\ud130, \uc608\ub97c \ub4e4\uc5b4 ’99\/06\/21’\uc744 \uc5f0\ub3c4 4\uc790\ub9ac \ub370\uc774\ud130 ‘1999’\ub85c \ubcc0\ud658\ud560 \uc218 \uc788\ub2e4.<\/p>\n
SQL> SELECT hire_date, salary
2 FROM employees
3 GROUP BY TO_CHAR(hire_date, ‘YYYY’);
SELECT hire_date, salary
*
ERROR at line 1:
ORA-00979: not a GROUP BY expression<\/p>\n
\uc704\uc758 \uc624\ub958\ub97c \ubcf4\uba74 SELECT \uc808\uc758 hire_date\uc758 \uce7c\ub7fc\uc774 GROUP BY\uc758 \ud45c\ud604\uc774 \uc544\ub2c8\ub77c\ub294 \uc624\ub958\ub97c \ub098\ud0c0\ub0b4\uace0 \uc788\ub2e4. \uc774\uc640 \uac19\uc740 \uc624\ub958\ub294 GROUP BY \uc808\uc744 \uc0ac\uc6a9\ud560 \ub54c SELECT\uc808\uc5d0 \uc0ac\uc6a9\ub420 \uc218 \uc788\ub294 \uce7c\ub7fc\uc774 \uc81c\ud55c\uc801\uc784\uc744 \ub9d0\ud574\uc900\ub2e4. \uc989, GROUP BY\uc808\uc5d0\uc11c \uc0ac\uc6a9\ud55c \uce7c\ub7fc\uacfc \uadf8\ub8f9 \ud568\uc218(\uc608\ub97c \ub4e4\uba74, \ud3c9\uade0\uc744 \uad6c\ud558\ub294 AVG() \ud568\uc218\ub098 \ucd5c\ub300 \uac12\uc744 MAX() \ud568\uc218 \ub4f1)\ub9cc\uc774 \uc0ac\uc6a9\ub420 \uc218 \uc788\ub2e4.
\ub530\ub77c\uc11c, GROUP BY \uc2dd\uc5d0\uc11c \uc0ac\uc6a9\ud55c \uce7c\ub7fc\uc774 TO_CHAR() \ud568\uc218\uc5d0 \uc758\ud574 \uac12\uc774 \ubcc0\ud615\ub418\uc5c8\ub2e4\uba74 \ubcc0\ud615\ub41c \ud615\ud0dc \uadf8\ub300\ub85c SELECT\uc808\uc5d0\uc11c \uc0ac\uc6a9\ub418\uc5b4\uc57c \ud55c\ub2e4.<\/p>\n
SQL> SELECT TO_CHAR(hire_date, ‘YYYY’), AVG(salary)
2 FROM employees
3 GROUP BY TO_CHAR(hire_date, ‘YYYY’);<\/p>\n
TO_C AVG(SALARY)
—- ———–
2000 5381.81818
1987 14200
1997 6460.71429
1994 9828.57143
1991 6000
1995 4525
1990 9000
1989 17000
1999 4938.88889
1996 8600
1993 17000<\/p>\n
TO_C AVG(SALARY)
—- ———–
1998 4873.91304<\/p>\n
12 rows selected.<\/p>\n
2.5 HAVING<\/p>\n
1) HAVING\uc808\uc758 \uc774\uc6a9
-> \ub9cc\uc57d \ucc98\uc74c GROUP BY \uc218\ud589 \uacb0\uacfc\ub85c\ubd80\ud130 \ubd80\uc11c\ubcc4 \ud3c9\uade0 \uae09\uc5ec\uac00 $10,000 \uc774\uc0c1\uc778 \ubd80\uc11c\ub9cc\uc744 \uc5bb\uace0\uc790 \ud55c\ub2e4\uba74 \uc5b4\ub5bb\uac8c \ud574\uc57c \ud560\uae4c? GROUP BY \uc808\uc758 \uacb0\uacfc\ub85c\ubd80\ud130 \ud2b9\uc815 \uc870\uac74\uc744 \ub9cc\uc871\ud558\ub294 \uac12\uc744 \uc5bb\uace0\uc790 \ud55c\ub2e4\uba74 HAVING\uc808\uc744 \uc0ac\uc6a9\ud560 \uc218 \uc788\ub2e4.<\/p>\n
SQL> SELECT department_id, AVG(salary)
2 FROM employees
3 GROUP BY department_id
4 HAVING AVG(salary) >= 10000;<\/p>\n
DEPARTMENT_ID AVG(SALARY)
————- ———–
70 10000
90 19333.3333
110 10150<\/p>\n
HAVING\uc808\uc740 GROUP BY \uc808\uc758 \uc218\ud589 \uacb0\uacfc\ub97c \ub300\uc0c1\uc73c\ub85c \ub2e4\uc2dc \uc870\uac74\uc744 \ub9cc\uc871\ud558\ub294 \uacb0\uacfc\ub97c \uc5bb\uc5b4\uc628\ub2e4.<\/p>\n
2) \ube44\ud6a8\uc728\uc801\uc778 HAVING\uc808
-> \uc544\ub798 SQL\ubb38\uc740 HAVING\uc808\uc774 \ube44\ud6a8\uc728\uc801\uc73c\ub85c \uc0ac\uc6a9\ub41c \uacbd\uc6b0\uc774\ub2e4. \uc694\uad6c \uc870\uac74\uc740 \ubd80\uc11c\ubcc4 \ucd5c\ub300 \uae09\uc5ec\ub97c \uc5bb\ub294 \uac83\uc774\ub2e4.<\/p>\n
SQL> SELECT department_id, MAX(salary)
2 FROM employees
3 GROUP BY department_id
4 HAVING department_id IN (10, 20);<\/p>\n
DEPARTMENT_ID MAX(SALARY)
————- ———–
20 13000
10 4400<\/p>\n
\uc5b4\ub5a4 \uad6c\ubb38\uc774 \uac1c\uc120\ub418\uc5b4\uc57c \ud558\ub098? SQL\ubb38\uc740 \uc6d0\ud558\ub294 \uacb0\uacfc\ub97c \uc5bb\uae30 \uc704\ud574 \ub2e4\uc591\ud558\uac8c \uc791\uc131\ub420 \uc218 \uc788\ub2e4. \ub530\ub77c\uc11c \ud558\ub098\uc758 SQL\ubb38\uc774 \ub2f5\uc774 \ub420 \uc218 \uc5c6\ub2e4. SQL\ubb38\uc5d0\uc11c\ub294 \ubb34\uc5c7\uc774 \ucd5c\uc120\uc758 \uc9c8\uc758\ubb38\uc774 \ub420 \uc218 \uc788\ub290\ub0d0\uac00 \ub370\uc774\ud130\ubca0\uc774\uc2a4\ub97c \uc774\uc6a9\ud558\uc5ec \uac1c\ubc1c\ud558\ub294 \uc5ec\ub7ec\ubd84\uc5d0\uac8c \uac00\uc7a5 \uc911\uc694\ud55c \ud575\uc2ec\uc774\ub77c \ud560 \uc218 \uc788\ub2e4.<\/p>\n
\uc704\uc758 \uc2e4\uc218\ub294 \uc5b4\ub514\uc5d0\uc11c \ube44\ub86f\ub418\uc5c8\ub294\uc9c0 \uc704 \uc9c8\uc758\ubb38\uc758 \uc218\ud589 \uacfc\uc815\uc744 \ub2e4\uc2dc \ud55c \ubc88 \uc0dd\uac01\ud574 \ubcf4\ub77c. \ub450 \uac00\uc9c0 \uc811\uadfc \ubc29\ubc95\uc744 \uc0dd\uac01\ud574 \ubcfc \uc218 \uc788\ub2e4.<\/p>\n
\uba3c\uc800 \ucd9c\ubc1c\uc740 \uac19\uc740 \uc9c8\uc758\ubb38\uc73c\ub85c\ubd80\ud130 \uc2dc\uc791\ud55c\ub2e4.<\/p>\n
SQL> SELECT department_id, salary
2 FROM employees;<\/p>\n
\uadf8\ub9ac\uace0 \uc55e\uc11c \uc218\ud589\ud55c \ubc29\ubc95\uc740 \uc774 \uc870\uac74\uc744 \ub9cc\uc871\ud558\ub294 107\ud589\uc744 \ub300\uc0c1\uc73c\ub85c GROUP BY \uc808\uc744 \uc218\ud589\ud558\uc5ec \uc544\ub798\uc640 \uac19\uc740 \uacb0\uacfc\ub97c \uc5bb\uc5c8\ub2e4.
SQL> SELECT department_id, MAX(salary)
2 FROM employees
3 GROUP BY department_id;<\/p>\n
DEPARTMENT_ID MAX(SALARY)
————- ———–
100 12000
30 11000
7000
20 13000
70 10000
90 24000
110 12000
50 8200
40 6500
80 14000
10 4400<\/p>\n
\uc774 \uacb0\uacfc\ub85c\ubd80\ud130 HAVING\uc808\uc5d0\uc11c \uc6d0\ud558\ub294 \ubd80\uc11c \uc544\uc774\ub514\uc5d0 \ud574\ub2f9\ud558\ub294 \uacb0\uacfc\ub97c \uc5bb\uace0 \uc788\ub2e4.<\/p>\n
\ub610 \ub2e4\ub978 \ubc29\ubc95\uc740 \uba3c\uc800 \ub300\uc0c1\uc774 \ub418\ub294 \ubd80\uc11c \uc544\uc774\ub514\ub97c WHERE\uc808\uc5d0\uc11c \uc81c\ud55c\ud558\ub294 \uac83\uc774\ub2e4.<\/p>\n
SQL> SELECT department_id, salary
2 FROM employees
3 WHERE department_id IN (10, 20);<\/p>\n
DEPARTMENT_ID SALARY
————- ———-
10 4400
20 13000
20 6000<\/p>\n
\uc55e\uc758 \ubc29\ubc95\uc740 107\ud589\uc5d0 \ub300\ud574 \ub3d9\uc77c \ubd80\uc11c \uc544\uc774\ub514\uc5d0 \ub300\ud574 \uae09\uc5ec \uce7c\ub7fc\uc758 \uac12\uc744 \ud558\ub098\uc529 \ube44\uad50\ud574 \uac00\uba74\uc11c \ucd5c\ub300 \uac12\uc744 \ucc3e\ub294 \uacfc\uc815\uc778\ub370 \ubc18\ud574 \uc5ec\uae30\uc11c\ub294 3\ud589\uc5d0 \ub300\ud574\uc11c\ub9cc \uc218\ud589\ud558\uace0 \uc788\ub2e4. \uc5b4\ub290 \uac83\uc774 \ub354 \ud6a8\uc728\uc801\uc778 \uc811\uadfc \ubc29\ubc95\uc774\uaca0\ub294\uac00?<\/p>\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
\uc694\uc57d. 1. \ud14c\uc774\ube14\uc5d0 \uc800\uc7a5\ub41c \ubaa8\ub4e0 \ub370\uc774\ud130\ub97c \ubcf4\uace0\uc790 \ud569\ub2c8\ub2e4. SELECT\uc640 FROM\uc808\ub85c \ub9cc\ub4e4\uc5b4 \ubcf4\ub77c.-> SELECT \uce7c\ub7fc1, \uce7c\ub7fc2 FROM \ud14c\uc774\ube14 2. \uc804\uccb4 \ub370\uc774\ud130 \uc911 \uc870\uac74\uc744 \ub9cc\uc871\ud558\ub294 \uac12\ub9cc \ubcf4\uace0 \uc2f6\uc2b5\ub2c8\ub2e4. WHERE \uc808\uc744 \uc774\uc6a9\ud574 \ubcf4\ub77c.-> WHERE \uce7c\ub7fc \uc870\uac74 \uac12 3. \uc77c\uc815\ud55c \uae30\ubd84\uc5d0 \uc758\ud574 \uc815\ub82c\ub418\uc5b4 \ud45c\ud604\ud558\uba74 \ubcf4\ub2e4 … Continue reading