尊龙凯时人生就是博

sqlÖÐsumº¯ÊýÔõôÓÃ

sqlÖеÄsum()º¯ÊýÓÃÓÚÅÌËãÊý×ÖÁеÄ×ܺÍ¡£Ëü¿ÉÒÔƾָ֤¶¨ÁС¢¹ýÂËÌõ¼þ¡¢ÓÖÃû¡¢·Ö×éºÍ¾ÛºÏ¶à¸öÁÐÀ´ÅÌËã×ܺÍ£¬µ«½ö´¦ÀíÊý×ÖÖµ£¬ºöÂÔnullÖµ¡£

SQL ÖÐ SUM() º¯ÊýµÄʹÓÃ

SQL ÖÐµÄ SUM() º¯ÊýÓÃÓÚÅÌËãÒ»×éÊý×ÖµÄ×ܺÍ¡£ËüÊÇÒ»¸ö¾ÛºÏº¯Êý£¬¿ÉÒÔ¶ÔÒ»×éÐлò±í¾ÙÐвÙ×÷¡£

Óï·¨£º

SUM(expression)

µÇ¼ºó¸´ÖÆ

ÆäÖУº

expression£ºÒªÇóºÍµÄÊý×Ö±í´ïʽ»òÁС£

ʹÓ÷½·¨£º

Ö¸¶¨ÇóºÍÁУºÖ¸¶¨ÒªÅÌËã×ܺ͵ÄÌض¨ÁС£ÀýÈ磺

SELECT SUM(salary) FROM employees;

µÇ¼ºó¸´ÖÆ

¹ýÂËЧ¹û£ºÊ¹Óà WHERE ×Ó¾ä¹ýÂËÊý¾Ý£¬½öÅÌËãÖª×ãÌض¨Ìõ¼þµÄÐС£ÀýÈ磺

SELECT SUM(salary) FROM employees WHERE department = 'Sales';

µÇ¼ºó¸´ÖÆ

ÓÖÃû£ºÎª SUM() º¯ÊýµÄÅÌËãЧ¹ûÖ¸¶¨Ò»¸öÌåÃû£¬ÒÔÀû±ãʹÓá£ÀýÈ磺

SELECT SUM(salary) AS total_salary FROM employees;

µÇ¼ºó¸´ÖÆ

·Ö×飺ʹÓà GROUP BY ×Ӿ佫Êý¾Ý·Ö×飬Ȼºó¶Ôÿ¸ö×éÅÌËã×ܺÍ¡£ÀýÈ磺

SELECT department, SUM(salary) AS total_salary
FROM employees
GROUP BY department;

µÇ¼ºó¸´ÖÆ

¾ÛºÏ¶à¸öÁУºSUM() º¯Êý¿ÉÒÔͬʱ¶Ô¶à¸öÁÐÅÌËã×ܺÍ¡£ÀýÈ磺

SELECT SUM(salary) + SUM(bonus) AS total_compensation
FROM employees;

µÇ¼ºó¸´ÖÆ

×¢ÖØÊÂÏ

SUM() º¯Êý½ö¶ÔÊý×ÖÖµÓÐÓá£

ÈôÊÇÒªÅÌËãµÄÁаüÀ¨ NULL Öµ£¬Ôò NULL Öµ½«±»ºöÂÔ¡£

SUM() º¯Êý¿ÉÒÔÓëÆäËû¾ÛºÏº¯Êý£¨ÀýÈç MIN()¡¢MAX()¡¢COUNT()£©Ò»ÆðʹÓá£

ÒÔÉϾÍÊÇsqlÖÐsumº¯ÊýÔõôÓõÄÏêϸÄÚÈÝ£¬¸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