{"id":5049,"date":"2021-04-15T17:13:28","date_gmt":"2021-04-15T09:13:28","guid":{"rendered":"https:\/\/nj.transwarp.cn:8180\/?p=5049"},"modified":"2025-07-31T16:16:41","modified_gmt":"2025-07-31T08:16:41","slug":"%e5%85%b3%e4%ba%8ecollect_list%e9%a1%ba%e5%ba%8f%e9%94%99%e4%b9%b1%e7%9a%84%e9%97%ae%e9%a2%98","status":"publish","type":"post","link":"https:\/\/kbwp.transwarp.cn\/?p=5049","title":{"rendered":"\u5173\u4e8ecollect_list\u987a\u5e8f\u9519\u4e71\u7684\u95ee\u9898"},"content":{"rendered":"

\u95ee\u9898\u63cf\u8ff0<\/h3>\n
\n

\u5ba2\u6237\u53cd\u9988\uff0c\u5728\u5bf9\u5217\u6570\u636e\u505aconcat_ws<\/code>\u65f6\uff0c\u5b50\u67e5\u8be2\u4e2dorder by<\/code>\u6392\u5e8f\u597d\u7684\u987a\u5e8f\u4f1a\u53d1\u751f\u9519\u4e71\u7684\u95ee\u9898\u3002\u672c\u6587\u4f1a\u5bf9\u8be5\u95ee\u9898\u8fdb\u884c\u573a\u666f\u590d\u73b0\uff0c\u5e76\u4e88\u4ee5\u89e3\u51b3\u65b9\u6848\u3002<\/p>\n

\"file\"<\/p>\n

\u95ee\u9898\u73b0\u8c61<\/h3>\n
\n

\u4e0b\u9762\u6784\u9020\u4e00\u4e2a\u7b80\u5355\u7684\u573a\u666f\u590d\u73b0\u5ba2\u6237\u7684\u95ee\u9898\uff0c\u9700\u8981\u53c2\u7167system.columns_v<\/code>\u6570\u636e\u5b57\u5178\u8868\u6784\u9020\u4e00\u4e2a\u6587\u672c\u8868\u3002\u5728\u63d2\u5165\u65f6\u7ed3\u5408mapred.reduce.tasks<\/code>\u8fd9\u4e2areduce\u53c2\u6570 + DISTRIBUTE BY<\/code>\u6765\u6784\u9020map\u6570\u4e0d\u4e3a1\u3002<\/p>\n

--\u6784\u9020\u6837\u4f8b\u8868\n> DROP TABLE IF EXISTS tbcolumns;\n> CREATE TABLE tbcolumns AS \n    SELECT\n    column_id,\n    column_name,\n    column_type,\n    table_name,\n    database_name,\n    commentstring,\n    default_value,\n    nullable,\n    unique_constraint,\n    column_length,\n    column_scale \nFROM system.columns_v WHERE 1=2;\n\n> SET mapred.reduce.tasks=3;\n> INSERT INTO tbcolumns SELECT * FROM system.columns_v DISTRIBUTE BY column_id;<\/code><\/pre>\n
--\u6d4b\u8bd5\u8bed\u53e5\n> SELECT\n    concat_ws(',',collect_list(column_name ))\nFROM\n    (SELECT * FROM tbcolumns WHERE table_name='emp' ORDER BY column_id ASC);<\/code><\/pre>\n
\u4e0a\u9762\u8fd9\u4e2asql\uff0c\u671f\u671b\u7684\u7ed3\u679c\u662f\uff0c\u5bf9SELECT column_name FROM tbcolumns WHERE table_name='emp' ORDER BY column_id asc<\/code>\u7684\u7ed3\u679c\u505a\u62fc\u63a5\uff0c\u987a\u5e8f\u4e0d\u80fd\u9519\u4e71\uff0c\u4e3aempno,ename,job,mgr,hiredate,sal,comm,deptno<\/code> \u3002<\/p>\n
\"file\"<\/p>\n
\u800c\u5b9e\u9645\u7684\u7ed3\u679c\uff0c\u987a\u5e8f\u53d1\u751f\u4e86\u9519\u4e71\uff0c\u5e76\u4e14\u6bcf\u6b21\u6267\u884c\u7684\u7ed3\u679c\u90fd\u4e0d\u4e00\u81f4\uff1a<\/p>\n
\"file\"<\/p>\n
\u89e3\u51b3\u65b9\u6cd5<\/h3>\n
\n
\u65b9\u68481\uff1a<\/strong><\/p>\n
SELECT\n    concat_ws(',',collect_list(column_name ))\nFROM\n    (\n    select column_name,row_number() over (order by column_id) from tbcolumns WHERE table_name='emp'\n);\n\n--\u6784\u9020\u591a\u4e2a\u8868\u7684\u67e5\u8be2\u8bed\u53e5\uff1a\nSELECT \n    \"select \" || cw || \" from \" || database_name || '.' || table_name ||';' \nFROM (\n    SELECT database_name,table_name,concat_ws(',',collect_list(column_name )) AS cw\n    FROM\n        (\n        select database_name,table_name,column_name,row_number() over (order by column_id) from system.columns_v\n--      WHERE table_name='emp'\n    )\n    GROUP BY  database_name,table_name\n);<\/code><\/pre>\n
\u65b9\u68482\uff1a<\/strong>
\n\u4ea7\u751f\u8fd9\u4e2a\u95ee\u9898\u7684\u6839\u672c\u539f\u56e0\u81ea\u7136\u5728MapReduce\uff0c\u5982\u679c\u542f\u52a8\u4e86\u591a\u4e8e\u4e00\u4e2amapper\/reducer\u6765\u5904\u7406\u6570\u636e\uff0cselect<\/code>\u51fa\u6765\u7684\u6570\u636e\u987a\u5e8f\u5c31\u51e0\u4e4e\u80af\u5b9a\u4e0e\u539f\u59cb\u987a\u5e8f\u4e0d\u540c\u4e86\u3002\u8003\u8651\u628amapper\u6570\u56fa\u5b9a\u62101\u6bd4\u8f83\u9ebb\u70e6\uff0c\u4e5f\u4e0d\u73b0\u5b9e\uff0c\u53ea\u4f7f\u7528sort_array<\/code>\u5982\u679c\u4e0d\u5bf9\u5217lpad<\/code>\u88650\u7684\u8bdd\u5bb9\u6613\u51fa\u73b0\u6392\u5e8f\u6df7\u4e71\uff0c\u6240\u4ee5\u8981\u8fc2\u56de\u5730\u89e3\u51b3\u95ee\u9898\uff1a\u628arank\u5217\u52a0\u8fdb\u6765\u518d\u8fdb\u884c\u4e00\u6b21\u6392\u5e8f\uff0c\u62fc\u63a5\u5b8c\u4e4b\u540e\u628arank\u5217\u53bb\u6389\u3002\u5982\u4e0b\uff1a<\/p>\n
select \n  regexp_replace(\n    concat_ws(',',sort_array(collect_list(concat_ws(':',lpad(cast(column_id as string),5,'0'),column_name)))),\n  '\\\\d+\\:','')\nfrom tbcolumns WHERE table_name='emp';<\/code><\/pre>\n
\"file\"<\/p>\n
\u8fd9\u91cc\u5c06rank\u5217\u4e5f\u5c31\u662fcolumn_id<\/code>\u653e\u5728\u4e86column_name<\/code>\u4e4b\u524d\uff0c\u7528\u5192\u53f7\u5206\u9694\uff0c\u7136\u540e\u7528sort_array<\/code>\u51fd\u6570\u5bf9collect_list<\/code>\u4e4b\u540e\u7684\u7ed3\u679c\u8fdb\u884c\u6392\u5e8f\uff08\u53ea\u652f\u6301\u5347\u5e8f\uff09\u3002<\/p>\n
\u7279\u522b\u6ce8\u610f\uff0crank\u5217\u5fc5\u987b\u8981\u5728\u9ad8\u4f4d\u8865\u8db3\u591f\u76840\u5bf9\u9f50\uff08\u8fd9\u91cc\u4f7f\u7528lpad<\/code>\u8ffd\u52a00\u5b57\u7b26\u7684\u65b9\u5f0f\uff09\uff0c\u56e0\u4e3a\u6392\u5e8f\u7684\u662f\u5b57\u7b26\u4e32\u800c\u4e0d\u662f\u6570\u5b57\uff0c\u5982\u679c\u4e0d\u88650\u7684\u8bdd\uff0c\u6309\u5b57\u5178\u5e8f\u6392\u5e8f\u5c31\u4f1a\u53d8\u62101, 10, 11, 12, 13, 2, 3, 4…\uff0c\u5c31\u4e0d\u5bf9\u4e86\u3002<\/p>\n
\u5c06\u6392\u5e8f\u7684\u7ed3\u679c\u62fc\u8d77\u6765\u4e4b\u540e\uff0c\u7528regexp_replace<\/code>\u51fd\u6570\u66ff\u6362\u6389\u5192\u53f7\u53ca\u5176\u524d\u9762\u7684\u6570\u5b57\uff0c\u5927\u529f\u544a\u6210\u3002<\/p>\n
FAQ:<\/strong>
\ngroup_concat<\/code>\u51fd\u6570\u4e5f\u540c\u7406<\/p>\n
DROP TABLE IF EXISTS test9911;\nCREATE TABLE test9911(deptno INT,name STRING ) CLUSTERED BY (deptno) INTO 3 BUCKETS STORED AS ORC_TRANSACTION;\n\nINSERT INTO test9911 select 1,'zhangsan' from system.dual;\nINSERT INTO test9911 select 2,'wangwu' from system.dual;\n\n--\u6b64\u65f6\u4e0b\u9762\u7684\u67e5\u8be2\u7ed3\u679c\u662f\u968f\u673a\u7684\uff0c\u6709\u65f6\u5019zhangsan,wangwu\uff0c\u662f\u6709\u65f6\u5019\u662fwangwu,zhangsan\nSELECT\n    group_concat(name,',')\nFROM\n    (SELECT * FROM test9911  ORDER BY deptno ASC);\n\n--\u89e3\u51b3\u65b9\u6848\uff1a\nSELECT\n    group_concat(name,',')\nFROM\n    (select NAME,row_number() over (order by DEPTNO) from test9911);<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
\u95ee\u9898\u63cf\u8ff0 \u5ba2\u6237\u53cd\u9988\uff0c\u5728\u5bf9\u5217\u6570\u636e\u505aconcat_ws\u65f6\uff0c\u5b50\u67e5\u8be2\u4e2dorder by\u6392\u5e8f\u597d\u7684\u987a\u5e8f\u4f1a\u53d1\u751f\u9519\u4e71\u7684\u95ee\u9898\u3002\u672c ..<\/p>\n
<\/div>\n
Read more<\/a><\/p>\n","protected":false},"author":12,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-5049","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"acf":[],"_links":{"self":[{"href":"https:\/\/kbwp.transwarp.cn\/index.php?rest_route=\/wp\/v2\/posts\/5049","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kbwp.transwarp.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kbwp.transwarp.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kbwp.transwarp.cn\/index.php?rest_route=\/wp\/v2\/users\/12"}],"replies":[{"embeddable":true,"href":"https:\/\/kbwp.transwarp.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5049"}],"version-history":[{"count":3,"href":"https:\/\/kbwp.transwarp.cn\/index.php?rest_route=\/wp\/v2\/posts\/5049\/revisions"}],"predecessor-version":[{"id":17006,"href":"https:\/\/kbwp.transwarp.cn\/index.php?rest_route=\/wp\/v2\/posts\/5049\/revisions\/17006"}],"wp:attachment":[{"href":"https:\/\/kbwp.transwarp.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5049"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kbwp.transwarp.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5049"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kbwp.transwarp.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5049"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}