<\/span><\/h3>\n\n\n\n\u5b66\u751f\u6bcf\u4e2a\u79d1\u76ee\u7684\u6210\u7ee9\u5355\u6d41\u6c34\uff0c\u8f6c\u5316\u6210\u6bcf\u4e2a\u5b66\u751f\u7684\u6210\u7ee9\u660e\u7ec6\u884c\u3002<\/p>\n\n\n\n
gbase> create table score(name varchar(100),subject varchar(100),score int);\r\nQuery OK, 0 rows affected (Elapsed: 00:00:00.75)\r\n\r\ngbase> insert into score values ('\u738b\u6d77', '\u8bed\u6587', 86),\r\n -> ('\u738b\u6d77', '\u6570\u5b66', 83),\r\n -> ('\u738b\u6d77', '\u82f1\u8bed', 93),\r\n -> ('\u9676\u4fca', '\u8bed\u6587', 88),\r\n -> ('\u9676\u4fca', '\u6570\u5b66', 84),\r\n -> ('\u9676\u4fca', '\u82f1\u8bed', 94),\r\n -> ('\u5218\u53ef', '\u8bed\u6587', 80),\r\n -> ('\u5218\u53ef', '\u6570\u5b66', 86),\r\n -> ('\u5218\u53ef', '\u82f1\u8bed', 88),\r\n -> ('\u674e\u6625', '\u8bed\u6587', 89),\r\n -> ('\u674e\u6625', '\u6570\u5b66', 80),\r\n -> ('\u674e\u6625', '\u82f1\u8bed', 87);;\r\nQuery OK, 12 rows affected (Elapsed: 00:00:00.41)\r\nRecords: 12 Duplicates: 0 Warnings: 0\r\n\r\nERROR:\r\nNo query specified\r\n\r\ngbase> select * from score;\r\n+--------+---------+-------+\r\n| name | subject | score |\r\n+--------+---------+-------+\r\n| \u738b\u6d77 | \u8bed\u6587 | 86 |\r\n| \u738b\u6d77 | \u6570\u5b66 | 83 |\r\n| \u738b\u6d77 | \u82f1\u8bed | 93 |\r\n| \u9676\u4fca | \u8bed\u6587 | 88 |\r\n| \u9676\u4fca | \u6570\u5b66 | 84 |\r\n| \u9676\u4fca | \u82f1\u8bed | 94 |\r\n| \u5218\u53ef | \u8bed\u6587 | 80 |\r\n| \u5218\u53ef | \u6570\u5b66 | 86 |\r\n| \u5218\u53ef | \u82f1\u8bed | 88 |\r\n| \u674e\u6625 | \u8bed\u6587 | 89 |\r\n| \u674e\u6625 | \u6570\u5b66 | 80 |\r\n| \u674e\u6625 | \u82f1\u8bed | 87 |\r\n+--------+---------+-------+\r\n12 rows in set (Elapsed: 00:00:00.00)\r\n<\/code><\/pre>\n\n\n\n<\/span>\u901a\u8fc7case when\u8ba1\u7b97\u65b0\u7684\u5217<\/span><\/h3>\n\n\n\n\u901a\u8fc7case when, \u5224\u65ad\u5f53\u524d\u5ba2\u6237\u5982\u679c\u662f\u67d0\u4e00\u79cd\u5b66\u79d1\uff0c\u5219\u8ba1\u7b97score\uff0c\u5426\u5219\u8bbe\u7f6e\u4e3a0.\u8fd9\u6837\uff0c\u901a\u8fc7\u4e0d\u540c\u5ba2\u6237\u7684case when\u5c31\u62ff\u5230\u4e86\u6bcf\u4e2a\u5b66\u79d1\u7684\u5206\u6570\u3002<\/p>\n\n\n\n
select name,\r\nselect *,\r\n case when subject='\u8bed\u6587' then score else 0 end '\u8bed\u6587' ,\r\n case when subject='\u6570\u5b66' then score else 0 end '\u6570\u5b66' ,\r\n case when subject='\u82f1\u8bed' then score else 0 end '\u82f1\u8bed' \r\nfrom score\n\ngbase> select *,\r\n -> case when subject='\u8bed\u6587' then score else 0 end '\u8bed\u6587' ,\r\n -> case when subject='\u6570\u5b66' then score else 0 end '\u6570\u5b66' ,\r\n -> case when subject='\u82f1\u8bed' then score else 0 end '\u82f1\u8bed'\r\n -> from score;\r\n+--------+---------+-------+--------+--------+--------+\r\n| name | subject | score | \u8bed\u6587 | \u6570\u5b66 | \u82f1\u8bed |\r\n+--------+---------+-------+--------+--------+--------+\r\n| \u738b\u6d77 | \u8bed\u6587 | 86 | 86 | 0 | 0 |\r\n| \u738b\u6d77 | \u6570\u5b66 | 83 | 0 | 83 | 0 |\r\n| \u738b\u6d77 | \u82f1\u8bed | 93 | 0 | 0 | 93 |\r\n| \u9676\u4fca | \u8bed\u6587 | 88 | 88 | 0 | 0 |\r\n| \u9676\u4fca | \u6570\u5b66 | 84 | 0 | 84 | 0 |\r\n| \u9676\u4fca | \u82f1\u8bed | 94 | 0 | 0 | 94 |\r\n| \u5218\u53ef | \u8bed\u6587 | 80 | 80 | 0 | 0 |\r\n| \u5218\u53ef | \u6570\u5b66 | 86 | 0 | 86 | 0 |\r\n| \u5218\u53ef | \u82f1\u8bed | 88 | 0 | 0 | 88 |\r\n| \u674e\u6625 | \u8bed\u6587 | 89 | 89 | 0 | 0 |\r\n| \u674e\u6625 | \u6570\u5b66 | 80 | 0 | 80 | 0 |\r\n| \u674e\u6625 | \u82f1\u8bed | 87 | 0 | 0 | 87 |\r\n+--------+---------+-------+--------+--------+--------+\r\n12 rows in set (Elapsed: 00:00:00.00)\r\n<\/code><\/pre>\n\n\n\n<\/span>\u901a\u8fc7\u805a\u5408\u8fd0\u7b97\uff0c\u6c47\u603b\u7ed3\u679c<\/span><\/h3>\n\n\n\n\u7406\u8bba\u4e0a\u4e00\u4e2a\u5b66\u751f\u4e00\u95e8\u529f\u8bfe\u4e0d\u4f1a\u6709\u591a\u4e2a\u6210\u7ee9\uff0c\u8fd9\u91cc\u5c31\u7528max\u51fd\u6570\uff0c\u5373\u4f7f\u6709\u591a\u4e2a\u4e5f\u53d6\u6700\u9ad8\u5206\u3002<\/p>\n\n\n\n
select name,\r\n sum(case when subject='\u8bed\u6587' then score else 0 end) '\u8bed\u6587' ,\r\n sum(case when subject='\u6570\u5b66' then score else 0 end) '\u6570\u5b66' ,\r\n sum(case when subject='\u82f1\u8bed' then score else 0 end) '\u82f1\u8bed' \r\nfrom score group by name;\n\ngbase> select name,\r\n -> sum(case when subject='\u8bed\u6587' then score else 0 end) '\u8bed\u6587' ,\r\n -> sum(case when subject='\u6570\u5b66' then score else 0 end) '\u6570\u5b66' ,\r\n -> sum(case when subject='\u82f1\u8bed' then score else 0 end) '\u82f1\u8bed'\r\n -> from score group by name;\r\n+--------+--------+--------+--------+\r\n| name | \u8bed\u6587 | \u6570\u5b66 | \u82f1\u8bed |\r\n+--------+--------+--------+--------+\r\n| \u9676\u4fca | 88 | 84 | 94 |\r\n| \u5218\u53ef | 80 | 86 | 88 |\r\n| \u674e\u6625 | 89 | 80 | 87 |\r\n| \u738b\u6d77 | 86 | 83 | 93 |\r\n+--------+--------+--------+--------+\r\n4 rows in set (Elapsed: 00:00:00.06)\r\n<\/code><\/pre>\n\n\n\n<\/span>\u5217\u8f6c\u884c<\/span><\/h2>\n\n\n\n\u7ee7\u7eed\u524d\u9762\u7684\u4f8b\u5b50\uff0c\u6211\u4eec\u5c06\u5b57\u6bb5\u540d\u6539\u6210\u62fc\u97f3\u3002<\/p>\n\n\n\n
<\/span>\u6570\u636e<\/span><\/h2>\n\n\n\ncreate table score2 as select name,\r\n sum(case when subject='\u8bed\u6587' then score else 0 end) yuwen ,\r\n sum(case when subject='\u6570\u5b66' then score else 0 end) shuxue ,\r\n sum(case when subject='\u82f1\u8bed' then score else 0 end) waiyu \r\nfrom score group by name;\n\ngbase> create table score2 as select name,\r\n -> sum(case when subject='\u8bed\u6587' then score else 0 end) yuwen ,\r\n -> sum(case when subject='\u6570\u5b66' then score else 0 end) shuxue ,\r\n -> sum(case when subject='\u82f1\u8bed' then score else 0 end) waiyu\r\n -> from score group by name;\r\nQuery OK, 4 rows affected (Elapsed: 00:00:01.33)\r\n\r\ngbase>\r\ngbase>\r\ngbase> select * from score2;\r\n+--------+-------+--------+-------+\r\n| name | yuwen | shuxue | waiyu |\r\n+--------+-------+--------+-------+\r\n| \u9676\u4fca | 88 | 84 | 94 |\r\n| \u5218\u53ef | 80 | 86 | 88 |\r\n| \u674e\u6625 | 89 | 80 | 87 |\r\n| \u738b\u6d77 | 86 | 83 | 93 |\r\n+--------+-------+--------+-------+\r\n4 rows in set (Elapsed: 00:00:00.03)\r\n<\/code><\/pre>\n\n\n\n<\/span>\u901a\u8fc7union all \u8f6c\u884c<\/span><\/h3>\n\n\n\nselect name,'\u8bed\u6587' subject, yuwen score from score2\r\nunion all\r\nselect name,'\u6570\u5b66' subject, shuxue score from score2\r\nunion all\r\nselect name,'\u82f1\u8bed' subject, waiyu score from score2\n\ngbase> select name,'\u8bed\u6587' subject, yuwen score from score2\r\n -> union all\r\n -> select name,'\u6570\u5b66' subject, shuxue score from score2\r\n -> union all\r\n -> select name,'\u82f1\u8bed' subject, waiyu score from score2;\r\n+--------+---------+-------+\r\n| name | subject | score |\r\n+--------+---------+-------+\r\n| \u9676\u4fca | \u8bed\u6587 | 88 |\r\n| \u5218\u53ef | \u8bed\u6587 | 80 |\r\n| \u674e\u6625 | \u8bed\u6587 | 89 |\r\n| \u9676\u4fca | \u6570\u5b66 | 84 |\r\n| \u5218\u53ef | \u6570\u5b66 | 86 |\r\n| \u674e\u6625 | \u6570\u5b66 | 80 |\r\n| \u9676\u4fca | \u82f1\u8bed | 94 |\r\n| \u5218\u53ef | \u82f1\u8bed | 88 |\r\n| \u674e\u6625 | \u82f1\u8bed | 87 |\r\n| \u738b\u6d77 | \u8bed\u6587 | 86 |\r\n| \u738b\u6d77 | \u6570\u5b66 | 83 |\r\n| \u738b\u6d77 | \u82f1\u8bed | 93 |\r\n+--------+---------+-------+\r\n12 rows in set (Elapsed: 00:00:00.00)\r\n<\/code><\/pre>\n\n\n\n<\/p>","protected":false},"excerpt":{"rendered":"
\u672c\u6587\u4ecb\u7ecd\u5e38\u89c1\u7684\u884c\u5217\u8f6c\u6362\u5728GBase8a\u6570\u636e\u5e93\u5185\u5b9e\u73b0\u7684\u65b9\u6cd5<\/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-2614","post","type-post","status-publish","format-standard","hentry","category-gbase8a"],"_links":{"self":[{"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/posts\/2614","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=2614"}],"version-history":[{"count":2,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/posts\/2614\/revisions"}],"predecessor-version":[{"id":2617,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/posts\/2614\/revisions\/2617"}],"wp:attachment":[{"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/media?parent=2614"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/categories?post=2614"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/tags?post=2614"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}