WHERE 節

WHERE節ã?¯å¿…è¦?ã?«å¿œã?˜ã?¦ã€?é?¸æŠžå¼?ã€?DELETE æ–‡ã€?UPDATE æ–‡ã?«ç½®ã??ã?“ã?¨ã?Œã?§ã??ã?¾ã?™ã€‚ WHERE節ã?®çœŸå?½å¼?ã?«åŸºã?¥ã?„ã?¦è¡Œã‚’é?¸æŠžã?™ã‚‹ã?“ã?¨ã?Œã?§ã??ã?¾ã?™ã€‚ å¼?ã?ŒçœŸã?¨è©•価ã?•れã?Ÿè¡Œã? ã?‘ã?Œã€?çµ?æžœã?«ã?¦è¿”ã?•れã?¾ã?™ã€‚ ã‚‚ã?—ã€?DELETEæ–‡ã?§ã?‚れã?°å‰Šé™¤ã?•れã€?UPDATEæ–‡ã?§ã?‚れã?°æ›´æ–°ã?•れã?¾ã?™ã€‚

æ§‹æ–‡

WHERE 真��

WHERE節ã?«ã?¯çœŸå?½å¼?ã‚’ç½®ã??ã?“ã?¨ã?Œã?§ã??ã?¾ã?™ã€‚一般的ã?ªå¼?ã?®è¡¨ã?«ä¸€è¦§ã?•れã?Ÿä¸€èˆ¬å¼?ã?®ã?»ã?¨ã‚“ã?©ã?¯ã€?真å?½å€¤ã?«ã?ªã‚‹ã?“ã?¨ã?Œã?§ã??ã?¾ã?™ã€‚

ã?•らã?«ã€?より一般的ã?ªçœŸå?½å¼?ã‚‚ã?‚りã?¾ã?™ã€‚表10ã?«ä¸€è¦§ã?•れã?ŸçœŸå?½æ¼”ç®—å­?ã?¯ã€?一ã?¤ã?‚ã‚‹ã?„ã?¯ã??れ以上ã?®ã‚ªãƒšãƒ©ãƒ³ãƒ‰ã‚’ã?¨ã‚Šã€?ã??ã?®å¼?ã?¯çœŸå?½å€¤ã‚’è¿”ã?—ã?¾ã?™ã€‚

例


-- ビジ�スクラス�席�予約�れ����
-- 便を見��る。
SELECT *
FROM FlightAvailability
WHERE business_seats_taken IS NULL
OR business_seats_taken = 0
-- EMP_ACT�EMPLOYEE���表を�����
-- EMP_ACT�全列��EMPLOYEEより従業員�苗字(LASTNAME)を加��
-- �果行���返�。
SELECT SAMP.EMP_ACT.*, LASTNAME
  FROM SAMP.EMP_ACT, SAMP.EMPLOYEE
  WHERE EMP_ACT.EMPNO = EMPLOYEE.EMPNO
-- 販売代�人�社員番��給料を�彼ら�部署�平�賃金�員数�共��
--返�。
-- ã?“ã?®å•?å?ˆã?›ã?§ã?¯ã€?ã?¾ã?šå•?å?ˆã?›ã?®ä¸€éƒ¨(DINFO)ã?«ã?¦ã€?AS節ã?§æ–°ã?—ã?„列å??を与ã?ˆã?¦ã€?
-- AVGSALARY�EMPCOUNT列�よ�WHERE節�使�れ��るDEPTNOを
-- å?–å¾—ã?§ã??るよã?†ã?«ã?™ã‚‹å¿…è¦?ã?Œã?‚る。
SELECT THIS_EMP.EMPNO, THIS_EMP.SALARY, DINFO.AVGSALARY, DINFO.EMPCOUNT
 FROM EMPLOYEE THIS_EMP,
   (SELECT OTHERS.WORKDEPT AS DEPTNO,
           AVG(OTHERS.SALARY) AS AVGSALARY,
           COUNT(*) AS EMPCOUNT
    FROM EMPLOYEE OTHERS
    GROUP BY OTHERS.WORKDEPT
   )AS DINFO
 WHERE THIS_EMP.JOB = 'SALESREP'
	   AND THIS_EMP.WORKDEPT = DINFO.DEPTNO