尊龙凯时人生就是博

mysqlÖеÄjoinÊÇʲô

mysql ÖÐµÄ join ÊÇÓÃÓÚ×éºÏ²î±ð±íÊý¾ÝµÄÅÌÎÊÏÂÁËüͨ¹ýÆ¥ÅäÁн¨ÉèÔÝʱ±í¡£join ÓÐËÄÖÖÀàÐÍ£ºinner join£¨½öÆ¥ÅäÁ½±íÖж¼±£´æµÄÐУ©¡¢left join£¨Ñ¡Ôñ×ó±íËùÓÐÐУ©¡¢right join£¨Ñ¡ÔñÓÒ±íËùÓÐÐУ©ºÍ full join£¨Ñ¡ÔñÁ½±íËùÓÐÐУ©¡£join ¿Éͨ¹ý×éºÏÊý¾Ý¡¢×èÖ¹×ÓÅÌÎÊ¡¢¼ò»¯ÅÌÎʵȷ½·¨Ìá¸ßЧÂʺͿɶÁÐÔ¡£

ʲôÊÇ MySQL ÖÐµÄ JOIN

JOIN ÊÇ MySQL ÖÐÓÃÓÚ×éºÏÀ´×Ô²î±ð±íµÄÊý¾ÝµÄÅÌÎÊÏÂÁî¡£Ëüͨ¹ý½ÏÁ¿Á½¸ö»ò¶à¸ö±íÖеÄÏàÆ¥ÅäÁÐÀ´½¨ÉèÔÝʱ±í£¬´Ó¶øÔÊÐíÎÒÃÇ´Ó¶à¸ö±íÖмìË÷Êý¾Ý¡£

JOIN µÄÀàÐÍ

ÓÐËÄÖÖÖ÷ÒªµÄ JOIN ÀàÐÍ£¬Ã¿ÖÖÀàÐͶ¼Æ¾Ö¤Æ¥ÅäÌõ¼þÒÔ²î±ðµÄ·½·¨×éºÏÊý¾Ý£º

INNER JOIN£º½öÑ¡ÔñÔÚËùÓÐÅþÁ¬±íÖж¼¾ßÓÐÆ¥ÅäÐеļͼ¡£

LEFT JOIN£ºÑ¡Ôñ×ó±íÖеÄËùÓмͼ£¬×ÝÈ»ËüÃÇÔÚÓÒ±íÖÐûÓÐÆ¥ÅäµÄÐС£

RIGHT JOIN£ºÑ¡ÔñÓÒ±íÖеÄËùÓмͼ£¬×ÝÈ»ËüÃÇÔÚ×ó±íÖÐûÓÐÆ¥ÅäµÄÐС£

FULL JOIN£¨»ò FULL OUTER JOIN£©£ºÑ¡ÔñÀ´×Ô×ó±íºÍÓÒ±íµÄËùÓмͼ£¬×ÝÈ»ËüÃÇÔÚÁíÒ»±íÖÐûÓÐÆ¥ÅäµÄÐС£

JOIN Óï·¨

ÒÔÏÂÊÇÒ»Ìõ INNER JOIN ÅÌÎʵÄÓï·¨£º

SELECT *
FROM table1
INNER JOIN table2
ON table1.column_name = table2.column_name;

µÇ¼ºó¸´ÖÆ

SELECT£ºÖ¸¶¨Òª¼ìË÷µÄÁС£

FROM£ºÖ¸¶¨ÒªÅþÁ¬µÄ±í¡£

INNER JOIN£ºÖ¸¶¨ JOIN ÀàÐÍ¡£

ON£ºÖ¸¶¨ÅþÁ¬Ìõ¼þ¡£

JOIN µÄÀûÒæ

JOIN ºÜÊÇÓÐÓã¬ÓÉÓÚËüÔÊÐíÎÒÃÇ£º

½«Êý¾Ý×éºÏÀ´×Ô¶à¸ö±í¡£

×èÖ¹×ÓÅÌÎÊ£¬´Ó¶øÌá¸ßÐÔÄÜ¡£

¼ò»¯ÖØ´óÅÌÎÊ£¬Ê¹Æä¸üÒ×ÓÚÃ÷È·¡£

ʾÀý

˼Á¿ÒÔÏÂÁ½¸ö±í£º

¿Í»§±í£º°üÀ¨¿Í»§ÐÅÏ¢£¬Èç¿Í»§ ID¡¢ÐÕÃû¡¢µØµã¡£

¶©µ¥±í£º°üÀ¨¶©µ¥ÐÅÏ¢£¬È綩µ¥ ID¡¢¿Í»§ ID¡¢²úÆ·Ãû³Æ¡£

ÎÒÃÇ¿ÉÒÔʹÓà JOIN À´»ñȡÿ¸ö¿Í»§¼°Æ䶩µ¥ÐÅÏ¢£º

SELECT *
FROM customers
INNER JOIN orders
ON customers.customer_id = orders.customer_id;

µÇ¼ºó¸´ÖÆ

Ч¹û½«°üÀ¨ÒÔÏÂÊý¾Ý£º

customer_id name address order_id product_name
1 John Doe 123 Main St 100 Product A
1 John Doe 123 Main St 200 Product B
2 Jane Smith 456 Elm St 300 Product C

ÒÔÉϾÍÊÇmysqlÖеÄjoinÊÇʲôµÄÏêϸÄÚÈÝ£¬¸ü¶àÇë¹Ø×¢±¾ÍøÄÚÆäËüÏà¹ØÎÄÕ£¡

ÃâÔð˵Ã÷£ºÒÔÉÏչʾÄÚÈÝȪԴÓÚÏàÖúýÌå¡¢ÆóÒµ»ú¹¹¡¢ÍøÓÑÌṩ»òÍøÂçÍøÂçÕûÀí£¬°æȨÕùÒéÓë±¾Õ¾Î޹أ¬ÎÄÕÂÉæ¼°¿´·¨Óë¿´·¨²»´ú±í尊龙凯时人生就是博ÂËÓÍ»úÍø¹Ù·½Ì¬¶È£¬Çë¶ÁÕß½ö×ö²Î¿¼¡£±¾ÎĽӴýתÔØ£¬×ªÔØÇë˵Ã÷À´ÓÉ¡£ÈôÄúÒÔΪ±¾ÎÄÇÖÕ¼ÁËÄúµÄ°æȨÐÅÏ¢£¬»òÄú·¢Ã÷¸ÃÄÚÈÝÓÐÈκÎÉæ¼°ÓÐÎ¥¹«µÂ¡¢Ã°·¸Ö´·¨µÈÎ¥·¨ÐÅÏ¢£¬ÇëÄúÁ¬Ã¦ÁªÏµ尊龙凯时人生就是博ʵʱÐÞÕý»òɾ³ý¡£

Ïà¹ØÐÂÎÅ

ÁªÏµ尊龙凯时人生就是博

18523999891

¿É΢ÐÅÔÚÏß×Éѯ

ÊÂÇéʱ¼ä£ºÖÜÒ»ÖÁÖÜÎ壬9:30-18:30£¬½ÚãåÈÕÐÝÏ¢

QR code
sitemap¡¢ÍøÕ¾µØͼ