<\/span><\/h3>\n\n\n\n8\u4e2a\u5b66\u751f\uff0c\u5e73\u5747\u5206\u6563\u57282\u4e2a\u7cfb\uff0c4\u4e2a\u73ed\u7ea7\u91cc\u9762\u3002<\/p>\n\n\n\n
create table s(Sno int ,Sname varchar(100),Ssex int,Sage int,Sdept varchar(100),Sclass varchar(100));\r\n-- \u8868\u4e2d\u5c5e\u6027\u5206\u522b\u4e3a\uff1a\u5b66\u53f7\u3001\u59d3\u540d\u3001\u6027\u522b\u3001\u5e74\u9f84\u548c\u7cfb\u540d\u3002\r\ninsert into s values(1,'\u5f201',1,18,'\u8ba1\u7b97\u673a\u7cfb','\u8ba1\u7b97\u673a\u7cfb1\u73ed');\r\ninsert into s values(2,'\u5f202',1,18,'\u8ba1\u7b97\u673a\u7cfb','\u8ba1\u7b97\u673a\u7cfb1\u73ed');\r\ninsert into s values(3,'\u5f203',1,18,'\u8ba1\u7b97\u673a\u7cfb','\u8ba1\u7b97\u673a\u7cfb2\u73ed');\r\ninsert into s values(4,'\u5f204',1,18,'\u8ba1\u7b97\u673a\u7cfb','\u8ba1\u7b97\u673a\u7cfb2\u73ed');\r\ninsert into s values(5,'\u5f205',1,18,'\u81ea\u52a8\u5316\u7cfb','\u81ea\u52a8\u5316\u7cfb1\u73ed');\r\ninsert into s values(6,'\u5f206',1,18,'\u81ea\u52a8\u5316\u7cfb','\u81ea\u52a8\u5316\u7cfb1\u73ed');\r\ninsert into s values(7,'\u5f207',1,18,'\u81ea\u52a8\u5316\u7cfb','\u81ea\u52a8\u5316\u7cfb2\u73ed');\r\ninsert into s values(8,'\u5f208',1,18,'\u81ea\u52a8\u5316\u7cfb','\u81ea\u52a8\u5316\u7cfb2\u73ed');\r\n\r\ngbase> select * from s;\r\n+------+-------+------+------+--------------+------------------+\r\n| Sno | Sname | Ssex | Sage | Sdept | Sclass |\r\n+------+-------+------+------+--------------+------------------+\r\n| 1 | \u5f201 | 1 | 18 | \u8ba1\u7b97\u673a\u7cfb | \u8ba1\u7b97\u673a\u7cfb1\u73ed |\r\n| 2 | \u5f202 | 1 | 18 | \u8ba1\u7b97\u673a\u7cfb | \u8ba1\u7b97\u673a\u7cfb1\u73ed |\r\n| 3 | \u5f203 | 1 | 18 | \u8ba1\u7b97\u673a\u7cfb | \u8ba1\u7b97\u673a\u7cfb2\u73ed |\r\n| 4 | \u5f204 | 1 | 18 | \u8ba1\u7b97\u673a\u7cfb | \u8ba1\u7b97\u673a\u7cfb2\u73ed |\r\n| 5 | \u5f205 | 1 | 18 | \u81ea\u52a8\u5316\u7cfb | \u81ea\u52a8\u5316\u7cfb1\u73ed |\r\n| 6 | \u5f206 | 1 | 18 | \u81ea\u52a8\u5316\u7cfb | \u81ea\u52a8\u5316\u7cfb1\u73ed |\r\n| 7 | \u5f207 | 1 | 18 | \u81ea\u52a8\u5316\u7cfb | \u81ea\u52a8\u5316\u7cfb2\u73ed |\r\n| 8 | \u5f208 | 1 | 18 | \u81ea\u52a8\u5316\u7cfb | \u81ea\u52a8\u5316\u7cfb2\u73ed |\r\n+------+-------+------+------+--------------+------------------+\r\n8 rows in set (Elapsed: 00:00:00.00)<\/code><\/pre>\n\n\n\n<\/span>\u79d1\u76ee(C)<\/span><\/h3>\n\n\n\n\u5c31\u8bed\u6587\u548c\u6570\u5b66\u4e24\u79d1<\/p>\n\n\n\n
create table c(Cno int,Cname varchar(100),Cteacher varchar(100),Ccredit int);\r\n-- \u8868\u4e2d\u5c5e\u6027\u5206\u522b\u4e3a\uff1a\u8bfe\u53f7\u3001\u8bfe\u540d\u3001\u6559\u5e08\u540d\u548c\u5b66\u5206\u3002\r\n\r\ninsert into c values(101,'\u8bed\u6587','\u8bed\u6587\u8001\u5e08',80);\r\ninsert into c values(102,'\u6570\u5b66','\u6570\u5b66\u8001\u5e08',70);\r\n\r\ngbase> select * from c;\r\n+------+--------+--------------+---------+\r\n| Cno | Cname | Cteacher | Ccredit |\r\n+------+--------+--------------+---------+\r\n| 101 | \u8bed\u6587 | \u8bed\u6587\u8001\u5e08 | 80 |\r\n| 102 | \u6570\u5b66 | \u6570\u5b66\u8001\u5e08 | 70 |\r\n+------+--------+--------------+---------+\r\n2 rows in set (Elapsed: 00:00:00.00)<\/code><\/pre>\n\n\n\n<\/span>\u6210\u7ee9(SC)<\/span><\/h3>\n\n\n\n\u6bcf\u7ec42\u4eba\uff0c<\/p>\n\n\n\n
- \u7b2c\u4e00\u7ec4\uff0c\u5168\u90e8\u53ca\u683c<\/li>
- \u7b2c\u4e8c\u7ec4\uff0c1\u95e8\u4e0d\u53ca\u683c<\/li>
- \u7b2c\u4e09\u7ec4\uff0c2\u95e8\u4e0d\u53ca\u683c<\/li>
- \u7b2c\u56db\u7ec4\uff0c3\u95e8\u4e0d\u53ca\u683c<\/li><\/ul>\n\n\n\n
create table sc(Sno int,Cno int,grade int);\r\n-- \u8868\u4e2d\u5c5e\u6027\u5206\u522b\u4e3a\uff1a\u5b66\u53f7\u3001\u8bfe\u53f7\u3001\u6210\u7ee9\u548c\u5b66\u5206\r\ninsert into sc values(1,101,140);\r\ninsert into sc values(1,102,120);\r\ninsert into sc values(2,101,120);\r\ninsert into sc values(2,102,100);\r\n\r\ninsert into sc values(3,101,120);\r\ninsert into sc values(3,102,120);\r\ninsert into sc values(4,101,120);\r\ninsert into sc values(4,102,60);\r\n\r\ninsert into sc values(5,101,120);\r\ninsert into sc values(5,102,120);\r\ninsert into sc values(6,101,70);\r\ninsert into sc values(6,102,60);\r\n\r\ninsert into sc values(7,101,120);\r\ninsert into sc values(7,102,60);\r\ninsert into sc values(8,101,70);\r\ninsert into sc values(8,102,60);\r\n\r\ngbase> select * from sc;\r\n+------+------+-------+\r\n| Sno | Cno | grade |\r\n+------+------+-------+\r\n| 1 | 101 | 140 |\r\n| 1 | 102 | 120 |\r\n| 2 | 101 | 120 |\r\n| 2 | 102 | 100 |\r\n| 3 | 101 | 120 |\r\n| 3 | 102 | 120 |\r\n| 4 | 101 | 120 |\r\n| 4 | 102 | 60 |\r\n| 5 | 101 | 120 |\r\n| 5 | 102 | 120 |\r\n| 6 | 101 | 70 |\r\n| 6 | 102 | 60 |\r\n| 7 | 101 | 120 |\r\n| 7 | 102 | 60 |\r\n| 8 | 101 | 70 |\r\n| 8 | 102 | 60 |\r\n+------+------+-------+\r\n16 rows in set (Elapsed: 00:00:00.00)<\/code><\/pre>\n\n\n\n<\/span>\u5206\u6790\u548c\u8fd0\u884c\u7ed3\u679c<\/span><\/h2>\n\n\n\n<\/span>\u6839\u636e\u6210\u7ee9,\u5173\u8054\u5b66\u79d1\u6700\u4f4e\u6807\u51c6\uff0c\u8ba1\u7b97\u662f\u5426\u53ca\u683c<\/span><\/h3>\n\n\n\n\u5982\u679c\u6210\u7ee9 sc.grade \u4f4e\u4e8e c.ccredit \u5219\u8ba4\u5b9a\u4e0d\u53ca\u683c\uff0c \u5bf9\u5e94isFail=1<\/p>\n\n\n\n
gbase> select sc.*,c.Ccredit,sc.grade<c.ccredit isFail from sc left join c on c. cno=sc.cno;\r\n+------+------+-------+---------+--------+\r\n| Sno | Cno | grade | Ccredit | isFail |\r\n+------+------+-------+---------+--------+\r\n| 1 | 101 | 140 | 80 | 0 |\r\n| 1 | 102 | 120 | 70 | 0 |\r\n| 2 | 101 | 120 | 80 | 0 |\r\n| 2 | 102 | 100 | 70 | 0 |\r\n| 3 | 101 | 120 | 80 | 0 |\r\n| 3 | 102 | 120 | 70 | 0 |\r\n| 4 | 101 | 120 | 80 | 0 |\r\n| 4 | 102 | 60 | 70 | 1 |\r\n| 5 | 101 | 120 | 80 | 0 |\r\n| 5 | 102 | 120 | 70 | 0 |\r\n| 6 | 101 | 70 | 80 | 1 |\r\n| 6 | 102 | 60 | 70 | 1 |\r\n| 7 | 101 | 120 | 80 | 0 |\r\n| 7 | 102 | 60 | 70 | 1 |\r\n| 8 | 101 | 70 | 80 | 1 |\r\n| 8 | 102 | 60 | 70 | 1 |\r\n+------+------+-------+---------+--------+\r\n16 rows in set (Elapsed: 00:00:00.00)\r\n<\/code><\/pre>\n\n\n\n<\/span>\u62ff\u5230\u5b66\u751f\u5bf9\u5e94\u7684\u7cfb\u548c\u73ed\u7ea7\u4fe1\u606f<\/span><\/h3>\n\n\n\ngbase> select sc.*,c.Ccredit,sc.grade<c.ccredit isFail,s.Sdept,s.Sclass from sc left join c on c.cno=sc.cno left join s on s.sno = sc.sno;\r\n+------+------+-------+---------+--------+--------------+------------------+\r\n| Sno | Cno | grade | Ccredit | isFail | Sdept | Sclass |\r\n+------+------+-------+---------+--------+--------------+------------------+\r\n| 1 | 101 | 140 | 80 | 0 | \u8ba1\u7b97\u673a\u7cfb | \u8ba1\u7b97\u673a\u7cfb1\u73ed |\r\n| 1 | 102 | 120 | 70 | 0 | \u8ba1\u7b97\u673a\u7cfb | \u8ba1\u7b97\u673a\u7cfb1\u73ed |\r\n| 2 | 101 | 120 | 80 | 0 | \u8ba1\u7b97\u673a\u7cfb | \u8ba1\u7b97\u673a\u7cfb1\u73ed |\r\n| 2 | 102 | 100 | 70 | 0 | \u8ba1\u7b97\u673a\u7cfb | \u8ba1\u7b97\u673a\u7cfb1\u73ed |\r\n| 3 | 101 | 120 | 80 | 0 | \u8ba1\u7b97\u673a\u7cfb | \u8ba1\u7b97\u673a\u7cfb2\u73ed |\r\n| 3 | 102 | 120 | 70 | 0 | \u8ba1\u7b97\u673a\u7cfb | \u8ba1\u7b97\u673a\u7cfb2\u73ed |\r\n| 4 | 101 | 120 | 80 | 0 | \u8ba1\u7b97\u673a\u7cfb | \u8ba1\u7b97\u673a\u7cfb2\u73ed |\r\n| 4 | 102 | 60 | 70 | 1 | \u8ba1\u7b97\u673a\u7cfb | \u8ba1\u7b97\u673a\u7cfb2\u73ed |\r\n| 5 | 101 | 120 | 80 | 0 | \u81ea\u52a8\u5316\u7cfb | \u81ea\u52a8\u5316\u7cfb1\u73ed |\r\n| 5 | 102 | 120 | 70 | 0 | \u81ea\u52a8\u5316\u7cfb | \u81ea\u52a8\u5316\u7cfb1\u73ed |\r\n| 6 | 101 | 70 | 80 | 1 | \u81ea\u52a8\u5316\u7cfb | \u81ea\u52a8\u5316\u7cfb1\u73ed |\r\n| 6 | 102 | 60 | 70 | 1 | \u81ea\u52a8\u5316\u7cfb | \u81ea\u52a8\u5316\u7cfb1\u73ed |\r\n| 7 | 101 | 120 | 80 | 0 | \u81ea\u52a8\u5316\u7cfb | \u81ea\u52a8\u5316\u7cfb2\u73ed |\r\n| 7 | 102 | 60 | 70 | 1 | \u81ea\u52a8\u5316\u7cfb | \u81ea\u52a8\u5316\u7cfb2\u73ed |\r\n| 8 | 101 | 70 | 80 | 1 | \u81ea\u52a8\u5316\u7cfb | \u81ea\u52a8\u5316\u7cfb2\u73ed |\r\n| 8 | 102 | 60 | 70 | 1 | \u81ea\u52a8\u5316\u7cfb | \u81ea\u52a8\u5316\u7cfb2\u73ed |\r\n+------+------+-------+---------+--------+--------------+------------------+\r\n16 rows in set (Elapsed: 00:00:00.00)\r\n<\/code><\/pre>\n\n\n\n<\/span>\u6839\u636e\u7cfb\uff0c\u73ed\u7ea7\uff0c\u7edf\u8ba1\u5404\u81ea\u7684\u4e0d\u53ca\u683c\u7387<\/span><\/h3>\n\n\n\n\u91c7\u7528\u4e0d\u5408\u683c\u7684\u4eba\u6570:sum(isFail) \u9664\u4ee5\u603b\u6570 count(*)\u5f97\u5230\u4e0d\u53ca\u683c\u7387\u3002<\/p>\n\n\n\n
gbase> select sdept,sclass,sum(isFail)\/count(*) failRate from ( select sc.*,c.Ccredit,sc.grade<c.ccredit isFail,s.Sdept,s.Sclass from sc left join c on c.cno=sc.cno left join s on s.sno = sc.sno) t group by sdept,sclass order by failrate desc;\r\n+--------------+------------------+----------+\r\n| sdept | sclass | failRate |\r\n+--------------+------------------+----------+\r\n| \u81ea\u52a8\u5316\u7cfb | \u81ea\u52a8\u5316\u7cfb2\u73ed | 0.7500 |\r\n| \u81ea\u52a8\u5316\u7cfb | \u81ea\u52a8\u5316\u7cfb1\u73ed | 0.5000 |\r\n| \u8ba1\u7b97\u673a\u7cfb | \u8ba1\u7b97\u673a\u7cfb2\u73ed | 0.2500 |\r\n| \u8ba1\u7b97\u673a\u7cfb | \u8ba1\u7b97\u673a\u7cfb1\u73ed | 0.0000 |\r\n+--------------+------------------+----------+\r\n4 rows in set (Elapsed: 00:00:00.00)\r\n<\/code><\/pre>\n\n\n\n<\/span>\u53ca\u683c\u7387\u7edf\u8ba1<\/span><\/h3>\n\n\n\n\u53ef\u4ee5\u75281\u51cf\u53bb\u4e0d\u53ca\u683c\u7387\uff0c\u4e5f\u53ef\u4ee5\u4ece\u539f\u59cb\u7684\u5224\u65ad\u5927\u4e8e\u7b49\u4e8e\u53ca\u683c\u7ebf\u8bbe\u7f6e isOK=1\u3002<\/p>\n\n\n\n
gbase> select sdept,sclass,sum(isOK)\/count(*) okRate from ( select sc.*,c.Ccredit,sc.grade>=c.ccredit isOK,s.Sdept,s.Sclass from sc left join c on c.cno=sc.cno left join s on s.sno = sc.sno) t group by sdept,sclass order by okRate desc;\r\n+--------------+------------------+--------+\r\n| sdept | sclass | okRate |\r\n+--------------+------------------+--------+\r\n| \u8ba1\u7b97\u673a\u7cfb | \u8ba1\u7b97\u673a\u7cfb1\u73ed | 1.0000 |\r\n| \u8ba1\u7b97\u673a\u7cfb | \u8ba1\u7b97\u673a\u7cfb2\u73ed | 0.7500 |\r\n| \u81ea\u52a8\u5316\u7cfb | \u81ea\u52a8\u5316\u7cfb1\u73ed | 0.5000 |\r\n| \u81ea\u52a8\u5316\u7cfb | \u81ea\u52a8\u5316\u7cfb2\u73ed | 0.2500 |\r\n+--------------+------------------+--------+\r\n4 rows in set (Elapsed: 00:00:00.01)\r\n<\/code><\/pre>","protected":false},"excerpt":{"rendered":"\u672c\u6587\u4ecb\u7ecd\u901a\u8fc7GBase 8a\u6570\u636e\u5e93\uff0c\u4ece\u5b66\u751f\u6bcf\u4e2a\u5b66\u79d1\u7684\u6210\u7ee9\uff0c\u7edf\u8ba1\u5404\u7cfb\uff0c\u5404\u73ed\u7ea7\uff0c\u4e0d\u5408\u683c\u7387\u7684\u6392\u884c\u60c5\u51b5\u3002<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-8049","post","type-post","status-publish","format-standard","hentry","category-gbase8a"],"_links":{"self":[{"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/posts\/8049","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/comments?post=8049"}],"version-history":[{"count":1,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/posts\/8049\/revisions"}],"predecessor-version":[{"id":8050,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/posts\/8049\/revisions\/8050"}],"wp:attachment":[{"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/media?parent=8049"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/categories?post=8049"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/tags?post=8049"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}