gbase> desc tt1;\r\n+-------+---------+------+-----+---------+-------+\r\n| Field | Type | Null | Key | Default | Extra |\r\n+-------+---------+------+-----+---------+-------+\r\n| id | int(11) | YES | | NULL | |\r\n+-------+---------+------+-----+---------+-------+\r\n1 row in set (Elapsed: 00:00:00.00)\r\n<\/code><\/pre>\n\n\n\ntt2\u8868\u662f2\u4e2a\u5b57\u6bb5\u7684\u8868\uff0c\u591a\u4e86\u4e00\u4e2avarchar\u7c7b\u578b\u7684name\u5b57\u6bb5\u3002<\/p>\n\n\n\n
gbase> desc tt2;\r\n+-------+--------------+------+-----+---------+-------+\r\n| Field | Type | Null | Key | Default | Extra |\r\n+-------+--------------+------+-----+---------+-------+\r\n| id | int(11) | YES | | NULL | |\r\n| name | varchar(100) | YES | | NULL | |\r\n+-------+--------------+------+-----+---------+-------+\r\n2 rows in set (Elapsed: 00:00:00.00)\r\n<\/code><\/pre>\n\n\n\ntt3\u4e5f\u662f2\u4e2a\u5b57\u6bb5\uff0c\u4f46name\u5b57\u6bb5\u6545\u610f\u8bbe\u7f6e\u6210bigint\u7c7b\u578b<\/p>\n\n\n\n
gbase> create table tt3(id int, name bigint);\r\nQuery OK, 0 rows affected (Elapsed: 00:00:00.25)\r\n\r\ngbase> insert into tt3 values(1,111);\r\nQuery OK, 1 row affected (Elapsed: 00:00:00.19)\r\n<\/code><\/pre>\n\n\n\n<\/span>\u4e0d\u6307\u5b9anull\u5e38\u91cf\u7c7b\u578b\uff0c\u5219\u9ed8\u8ba4\u4e3avarbinary<\/span><\/h2>\n\n\n\n\u5982\u4e0b\u7684tt2\u8868\uff0c\u7528 null \u751f\u6210name\u5b57\u6bb5\uff0c\u56e0\u4e3a\u6ca1\u6709\u6307\u5b9a\u7c7b\u578b\uff0c\u5219\u9ed8\u8ba4\u662fvarbinary\u3002<\/p>\n\n\n\n
gbase> create table tt6 as select id,null name from tt1;\r\nQuery OK, 9 rows affected (Elapsed: 00:00:01.18)\r\n\r\ngbase> desc tt6;\r\n+-------+--------------+------+-----+---------+-------+\r\n| Field | Type | Null | Key | Default | Extra |\r\n+-------+--------------+------+-----+---------+-------+\r\n| id | int(11) | YES | | NULL | |\r\n| name | varbinary(1) | YES | | NULL | |\r\n+-------+--------------+------+-----+---------+-------+\r\n2 rows in set (Elapsed: 00:00:00.00)\r\n<\/code><\/pre>\n\n\n\n<\/span>\u901a\u8fc7cast\u5f3a\u5236\u6307\u5b9anull\u7684\u7c7b\u578b<\/span><\/h2>\n\n\n\ngbase> create table tt8 select id,cast(null as int) name from tt1;\r\nQuery OK, 9 rows affected (Elapsed: 00:00:00.56)\r\n\r\ngbase> desc tt8;\r\n+-------+-----------+------+-----+---------+-------+\r\n| Field | Type | Null | Key | Default | Extra |\r\n+-------+-----------+------+-----+---------+-------+\r\n| id | int(11) | YES | | NULL | |\r\n| name | bigint(1) | YES | | NULL | |\r\n+-------+-----------+------+-----+---------+-------+\r\n2 rows in set (Elapsed: 00:00:00.00)\r\n<\/code><\/pre>\n\n\n\n<\/span>2\u8868union\u65f6\u5176\u4e2d\u4e00\u4e2a\u5305\u542b\u4e86\u660e\u786e\u7c7b\u578b\u65f6\u53ef\u4ee5\u6b63\u786e\u8bc6\u522b<\/span><\/h2>\n\n\n\n\u867d\u7136\u5e26null\u5e38\u91cf\u7684tt1\u5728union\u7684\u524d\u9762\uff0c\u4f46\u7ed3\u679c\u4f9d\u7136\u6b63\u786e\u8bc6\u522b\u4e86\u7c7b\u578b\u4e3att2\u7684varchar\u3002<\/p>\n\n\n\n
gbase> create table tt4 as select id,null name from tt1 union all select * from tt2;\r\nQuery OK, 18 rows affected (Elapsed: 00:00:00.63)\r\n\r\ngbase> desc tt4;\r\n+-------+--------------+------+-----+---------+-------+\r\n| Field | Type | Null | Key | Default | Extra |\r\n+-------+--------------+------+-----+---------+-------+\r\n| id | int(11) | YES | | NULL | |\r\n| name | varchar(100) | YES | | NULL | |\r\n+-------+--------------+------+-----+---------+-------+\r\n2 rows in set (Elapsed: 00:00:00.00)\r\n<\/code><\/pre>\n\n\n\n<\/span>\u591a\u8868union\u65f6\u5bf9\u5e94\u5217\u7684\u7c7b\u578b\u5fc5\u987b\u4e00\u81f4<\/span><\/h2>\n\n\n\n\u5982\u679c\u4e0d\u4e00\u81f4\uff0c\u5219\u4f1a\u62a5\u9519\uff0c\u6bd4\u5982\u5982\u4e0b\u7b2c3\u4e2a\u8868tt3\u662fbigint\u7c7b\u578b\uff0c\u7b2c2\u4e2a\u8868tt2\u662fvarchar\u7c7b\u578b\uff0c\u8bed\u53e5\u62a5\u9519\u3002<\/p>\n\n\n\n
gbase> create table tt7 as select id,null name from tt1 union select * from tt2 union all select * from tt3;\r\nERROR 1733 (HY000): (GBA-01EX-700) Gbase general error: UNION\/INTERSECT\/MINUS of non-matching columns: VARCHAR UNION\/INTERSECT\/MINUS LONGLONG\r\n\r\n<\/code><\/pre>\n\n\n\n\u5fc5\u987b\u901a\u8fc7cast\u5f3a\u5236\u8f6c\u5316\u6307\u5b9a\u7c7b\u578b<\/p>\n\n\n\n
gbase> create table tt7 as select id,null name from tt1 union select * from tt2 union all select id,cast(name as char) from tt3;\r\nQuery OK, 17 rows affected (Elapsed: 00:00:00.59)\r\n\r\ngbase> desc tt7;\r\n+-------+--------------+------+-----+---------+-------+\r\n| Field | Type | Null | Key | Default | Extra |\r\n+-------+--------------+------+-----+---------+-------+\r\n| id | int(11) | YES | | NULL | |\r\n| name | varchar(100) | YES | | NULL | |\r\n+-------+--------------+------+-----+---------+-------+\r\n2 rows in set (Elapsed: 00:00:00.00)\r\n<\/code><\/pre>","protected":false},"excerpt":{"rendered":"\u5357\u5927\u901a\u7528GBase 8a\u91cc\uff0cnull\u5e38\u91cf\u6570\u636e\uff0c\u6ce8\u610f\u4e0d\u662f\u67d0\u4e2a\u5b57\u6bb5\u7684\u6570\u503c\u4e3anull,\u800c\u662f\u4e00\u4e2anull\u5e38\u91cf\uff0c\u5982\u679c\u4e0d\u6307\u5b9a\u7c7b\u578b\uff0c\u9ed8\u8ba4\u672avarbinary\u3002\u53ef\u4ee5\u901a\u8fc7cast\u5f3a\u5236\u6307\u5b9a\u7c7b\u578b\uff0c\u4e5f\u53ef\u4ee5\u6839\u636e\u4e0a\u4e0b\u6587\uff0c\u4ece\u5176\u5b83\u5bf9\u5e94\u5b57\u6bb5\u53d6\u5f97\u7c7b\u578b\uff0c\u6bd4\u5982union\u7684\u5176\u5b83\u8868\u7684\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-5996","post","type-post","status-publish","format-standard","hentry","category-gbase8a"],"_links":{"self":[{"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/posts\/5996","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=5996"}],"version-history":[{"count":3,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/posts\/5996\/revisions"}],"predecessor-version":[{"id":5999,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/posts\/5996\/revisions\/5999"}],"wp:attachment":[{"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/media?parent=5996"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/categories?post=5996"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.gbase8.cn\/en\/wp-json\/wp\/v2\/tags?post=5996"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}