真å?½å¼?ã?¯WHERE節やãƒ?ェック制約ã?«ç½®ã??ã?“ã?¨ã?Œã?§ã??ã?¾ã?™ã€‚ ãƒ?ェック制約ã?«ç½®ã??真å?½å¼?ã?«ã?¯ã€?ã?“ã?“ã?§è¨˜è¿°ã?•れã?¦ã?„ã?ªã?„制é™?ã?Œã?‚りã?¾ã?™ã€‚ 詳細ã?¯CONSTRAINT 節をå?‚ç…§ã?—ã?¦ã??ã? ã?•ã?„。 WHERE節ã?«ç½®ã??真å?½å¼?ã?®æ§‹æ–‡ã?¯æŸ”軟ã?ªã‚‚ã?®ã?¨ã?ªã?£ã?¦ã?„ã?¾ã?™ã€‚具体的ã?ªä¾‹ã?¯ã€?WHERE節をå?‚ç…§ã?—ã?¦ã??ã? ã?•ã?„。
演算å? | 説明ã?¨ä¾‹ | æ§‹æ–‡ |
---|---|---|
AND, OR, NOT | オペランド��る真��を評価���。 (orig_airport = 'SFO') OR
(dest_airport = 'GRU')
-- 真を返�。
|
{ å¼? AND å¼?| å¼? OR å¼? | NOT å¼? } |
比較演算å? | <, =, >, <=, >=, <> ã?¯ã€?å…¨ã?¦ã?®çµ„ã?¿è¾¼ã?¿ã?®åž‹ã?«é?©ç”¨ã?™ã‚‹ã?“ã?¨ã?Œã?§ã??ã?¾ã?™ã€‚ DATE('1998-02-26') <
DATE('1998-03-01')
-- 真を返�。
|
å¼? { < | = | > | <= | >= | <> } å¼? |
IS NULL, IS NOT NULL | å¼?ã?®çµ?æžœã?Œç©ºã?‹ã??ã?†ã?§ã?ªã?„ã?‹ã‚’判定ã?—ã?¾ã?™ã€‚
WHERE MiddleName IS NULL |
å¼? IS [ NOT ] NULL |
LIKE | æ–‡å—å¼?ã?Œæ–‡å—パターンã?¨ä¸€è‡´ã?™ã‚‹ã?‹ã‚’判定ã?—ã?¾ã?™ã€‚æ–‡å—パターンã?«ã?¯ä¸€ã?¤ä»¥ä¸Šã?®ãƒ¯ã‚¤ãƒ«ãƒ‰ã‚«ãƒ¼ãƒ‰ã?Œå?«ã?¾ã‚Œã?¾ã?™ã€‚
%ã?¯æœ€åˆ?ã?®æ–‡å—å¼?ã?«ã?¦ã€?該当ã?™ã‚‹ä½?ç½®ã?®ä»»æ„?ã?®æ–‡å—æ•°(0æ–‡å—以上)ã?®æ–‡å—列ã?«ä¸€è‡´ã?—ã?¾ã?™ã€‚ _ã?¯æ–‡å—å¼?ã?«ã?¦ã€?該当ã?™ã‚‹ä½?ç½®ã?®ä¸€æ–‡å—ã?«ä¸€è‡´ã?—ã?¾ã?™ã€‚ ã??れ以外ã?®æ–‡å—ã?¯ã€?æ–‡å—å¼?ã?«ã?¦è©²å½“ã?™ã‚‹ä½?ç½®ã?®å?Œã?˜æ–‡å—ã?«ä¸€è‡´ã?—ã?¾ã?™ã€‚
city LIKE 'Sant_' %ã‚„_をワイルドカードã?§ã?¯ã?ªã?„æ–‡å—ã?¨ã?™ã‚‹ã?«ã?¯ã€?ESCAPE節ã?§æŒ‡å®šã?™ã‚‹ã‚¨ã‚¹ã‚±ãƒ¼ãƒ—æ–‡å—を使ã?£ã?¦æ–‡å—をエスケープã?—ã?¾ã?™ã€‚
SELECT a FROM tabA WHERE a LIKE '%=_' ESCAPE '=' 注:
LIKEã?«ã‚ˆã‚‹æ¯”較ã?§ã?¯Derbyã?¯ã€?個々ã?®æ–‡å—ã‚’é?žãƒ¡ã‚¿æ–‡å—ã?¨æ¯”較ã?—ã?¾ã?™ã€‚ã?“れã?¯Derbyã?Œ=ã?«ã‚ˆã‚‹æ¯”較ã?®ã?¨ã??行ã?†å‡¦ç?†ã?¨ã?¯é?•ã?„ã?¾ã?™ã€‚=ã?«ã‚ˆã‚‹æ¯”較ã?§ã?¯å·¦è¾ºã?®æ–‡å—列全体ã?Œã€?=演算å?ã?®å?³è¾ºã?®æ–‡å—列全体ã?¨æ¯”較ã?•れã?¾ã?™ã€‚より詳細ã?ªæƒ…å ±ã?«ã?¤ã?„ã?¦ã?¯ã€?Derby ディベãƒãƒƒãƒ‘ーズ ガイドã?®Derbyã?«ã?Šã?‘ã‚‹æ–‡å—ã?®ç…§å?ˆã‚’å?‚ç…§ã?—ã?¦ã??ã? ã?•ã?„。
|
æ–‡å—å¼? [ NOT ] LIKE ワイルドカードã?®ã?‚ã‚‹æ–‡å—å¼? [ ESCAPE 'エスケープ文å—'] |
BETWEEN | 最��オペランド�二�目�三�目�オペランド�間�値��る�を判定���。二�目�オペランド�三�目�オペランドより���値���れ��り��ん。
ã?“ã?®æ¼”ç®—å?ã?¯<=ã?¨>=ã?Œé?©ç”¨ã?§ã??ã‚‹åž‹ã?«å¯¾ã?—ã?¦ã?®ã?¿é?©ç”¨ã?§ã??ã?¾ã?™ã€‚
WHERE booking_date BETWEEN DATE('1998-02-26') AND DATE('1998-03-01') |
å¼? [ NOT ] BETWEEN å¼? AND å¼? |
IN | 表副���や値�並��作用���。左辺���値�表副���や値�並����れる�ら��真を返���。���表副����複数行を返�������ん��列�一����れ��り��ん。WHERE booking_date NOT IN (SELECT booking_date FROM HotelBookings WHERE rooms_available = 0) |
{ � [ NOT ] IN 表副��� | � [ NOT ] IN ( � [, � ]* ) } |
EXISTS | 表副å•?å?ˆã?›ã?«ä½œç”¨ã?—ã?¦ã€?ã??ã?®è¡¨å‰¯å•?å?ˆã?›ã?Œè¡Œã‚’è¿”ã?™ã?ªã‚‰ã?°çœŸã‚’è¿”ã?—ã€?行ã?Œè¿”らã?ªã?„ã?ªã‚‰ã?°å?½ã‚’è¿”ã?—ã?¾ã?™ã€‚表副å•?å?ˆã?›ã?¯è¤‡æ•°ã?®åˆ—(*を使ã?£ã?Ÿå ´å?ˆã?«é™?りã?¾ã?™ã€‚)や行を返ã?™ã?“ã?¨ã?Œã?§ã??ã?¾ã?™ã€‚WHERE EXISTS (SELECT * FROM Flights WHERE dest_airport = 'SFO' AND orig_airport = 'GRU') |
[NOT] EXISTS 表副��� |
定é‡?比較 | 定é‡?比較ã?¯ALLã€?ANYã€?SOMEã?®ä½•れã?‹ã?Œé?©ç”¨ã?•れã?Ÿæ¯”較演算å?
(<,=, >, <=, >=, <>)��り��。
ã?“れã?¯è¡¨å‰¯å•?å?ˆã?›ã?«ä½œç”¨ã?—ã?¾ã?™ã€‚表副å•?å?ˆã?›ã?¯è¤‡æ•°ã?®è¡Œã‚’è¿”ã?™ã?“ã?¨ã?Œã?§ã??ã?¾ã?™ã?Œã€?å?˜ä¸€ã?®åˆ—ã?—ã?‹è¿”ã?›ã?¾ã?›ã‚“。 ALLã?ŒæŒ‡å®šã?•れã?Ÿå ´å?ˆã€?表副å•?å?ˆã?›ã?Œè¿”ã?™å…¨ã?¦ã?®å€¤ã?«å¯¾ã?—ã?¦ã€?比較ã?®çµ?æžœã?ŒçœŸã?§ã?ªã?‘れã?°ã?ªã‚Šã?¾ã?›ã‚“。ANYã?ªã?„ã?—SOMEã?ŒæŒ‡å®šã?•れã?Ÿå ´å?ˆã€?表副å•?å?ˆã?›ã?Œè¿”ã?™ä½•れã?‹ã?®å€¤ã?«å¯¾ã?—ã?¦ã€?比較ã?®çµ?æžœã?ŒçœŸã?§ã?‚ã‚‹å¿…è¦?ã?Œã?‚りã?¾ã?™ã€‚ANYã?¨SOMEã?¯å?Œã?˜æ„?味ã?§ã?™ã€‚
WHERE normal_rate < ALL (SELECT budget/550 FROM Groups) |
å¼? 比較演算å? { ALL | ANY | SOME } 表副å•?å?ˆã?› |