JOIN演算ã?¯FROM 節ã?®TableExpressionã?«ç½®ã??ã?“ã?¨ã?Œã?§ã??ã€?2表ã?®é–“ã?®çµ?å?ˆã‚’記述ã?—ã?¾ã?™ã€‚(WHERE節ã?«ã?¦"WHERE t1.col1 = t2.col2"ç‰ã?¨æ›¸ã?„ã?¦ã€?明示的ã?«ç‰ä¾¡æ€§ã?®åˆ¤å®šå¼?を記述ã?™ã‚‹ã?“ã?¨ã?§ã‚‚ã€?çµ?å?ˆã‚’実ç?¾ã?™ã‚‹ã?“ã?¨ã‚‚ã?§ã??ã?¾ã?™ã€‚)
JOINå¼?
join節ã?«ã‚ˆã‚Š2表ã?®é–“ã?®çµ?å?ˆã‚’明示的ã?«æŒ‡å®šã?—ã?¾ã?™ã€‚INNER JOIN 演算をå?‚ç…§ã?—ã?¦ã??ã? ã?•ã?„。
join節ã?«ã‚ˆã‚Š2表ã?®é–“ã?®çµ?å?ˆã‚’明示的ã?«æŒ‡å®šã?—ã?¾ã?™ã€‚ã?¾ã?Ÿæœ€åˆ?ã?®è¡¨ã?«ã?¦ä¸€è‡´è¡Œã?ŒäºŒã?¤ç›®ã?®è¡¨ã?«ã?ªã?„行も残りã?¾ã?™ã€‚LEFT OUTER JOIN演算をå?‚ç…§ã?—ã?¦ã??ã? ã?•ã?„。
join節ã?«ã‚ˆã‚Š2表ã?®é–“ã?®çµ?å?ˆã‚’明示的ã?«æŒ‡å®šã?—ã?¾ã?™ã€‚ã?¾ã?ŸäºŒã?¤ç›®ã?®è¡¨ã?«ã?¦ä¸€è‡´è¡Œã?Œæœ€åˆ?ã?®è¡¨ã?«ã?ªã?„行も残りã?¾ã?™ã€‚RIGHT OUTER JOIN 演算をå?‚ç…§ã?—ã?¦ã??ã? ã?•ã?„。
ã?©ã?®å ´å?ˆã?§ã‚‚ã€?çµ?å?ˆã?•れã?Ÿè¡¨ã?®ç‰‡æ–¹ã‚‚ã?—ã??ã?¯ä¸¡æ–¹ã?«ã€?outer join節ã?‚ã‚‹ã?„ã?¯WHERE 節ã?§ã€?è¿½åŠ ã?®çµžè¾¼æ?¡ä»¶ã‚’ç½®ã??ã?“ã?¨ã?Œã?§ã??ã?¾ã?™ã€‚
çµ?å?ˆã?«ã?©ã?®ã‚ˆã?†ã?ªæœ€é?©åŒ–ã?Œè¡Œã‚?れるã?‹ã?«ã?¤ã?„ã?¦ã?¯ã€?Derbyã?®ãƒ?ューニングをå?‚ç…§ã?—ã?¦ã??ã? ã?•ã?„。