{"id":10683,"date":"2023-10-16T09:25:36","date_gmt":"2023-10-16T01:25:36","guid":{"rendered":"https:\/\/nj.transwarp.cn:8180\/?p=10683"},"modified":"2023-10-16T09:25:35","modified_gmt":"2023-10-16T01:25:35","slug":"%e9%80%9a%e8%bf%87tab_col_stats%e6%9f%a5%e7%9c%8b%e7%bb%9f%e8%ae%a1%e4%bf%a1%e6%81%af","status":"publish","type":"post","link":"https:\/\/kbwp.transwarp.cn\/?p=10683","title":{"rendered":"\u901a\u8fc7TAB_COL_STATS\u67e5\u770b\u7edf\u8ba1\u4fe1\u606f"},"content":{"rendered":"<h3>\u6982\u8981\u63cf\u8ff0<\/h3>\n<p>\u672c\u6587\u4e3b\u8981\u4ecb\u7ecd\u5982\u4f55\u901a\u8fc7\u6536\u96c6\u8868\u7684\u5217\u7edf\u8ba1\u4fe1\u606f\uff0c\u5bf9<code>TAB_COL_STATS<\/code>\u7684\u7ed3\u679c\u8fdb\u884c\u5206\u6790\u3002<\/p>\n<hr \/>\n<h3>\u8be6\u7ec6\u8bf4\u660e<\/h3>\n<p>\u9996\u5148\u6211\u4eec\u521b\u5efa\u6837\u4f8b\u8868\uff0c\u5e76\u63d2\u5165\u6570\u636e \uff08\u5efa\u8868\u8bed\u53e5\u548c\u63d2\u5165\u8bed\u53e5\u89c1\u7ed3\u5c3e\u5185\u5bb9\uff09\uff0c\u6570\u636e\u5982\u4e0b<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/2023\/08\/image-1692770931483.png\" alt=\"file\" \/><\/p>\n<p>\u6267\u884c<code>analyze<\/code>\u547d\u4ee4\uff0c\u5bf9\u8868\u7684\u5217\u4fe1\u606f\u8fdb\u884c\u7edf\u8ba1\u6536\u96c6<\/p>\n<pre><code class=\"language-sql\">> ANALYZE TABLE default.emp COMPUTE STATISTICS FOR COLUMNS;<\/code><\/pre>\n<p>\u6536\u96c6\u5230\u7684\u7edf\u8ba1\u4fe1\u606f\uff0c\u9700\u8981\u5230\u5143\u6570\u636e\u5e93\uff08txsql\/kundb\uff09\u8fdb\u884c\u67e5\u770b:<\/p>\n<pre><code class=\"language-sql\">> SELECT * FROM TAB_COL_STATS WHERE DB_NAME='default' and TABLE_NAME='emp' order by cs_id asc;<\/code><\/pre>\n<p>\u4e0b\u9762\u662f<code>TAB_COL_STATS<\/code>\u8868\u7684\u5217\u4fe1\u606f\u8bf4\u660e<\/p>\n<table>\n<thead>\n<tr>\n<th style=\"text-align: left;\">\u5217\u540d<\/th>\n<th style=\"text-align: left;\">\u5217\u8bf4\u660e<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"text-align: left;\">cs_id<\/td>\n<td style=\"text-align: left;\">id<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">db_name<\/td>\n<td style=\"text-align: left;\">\u5e93\u540d<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">table_name<\/td>\n<td style=\"text-align: left;\">\u8868\u540d<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">column_name<\/td>\n<td style=\"text-align: left;\">\u5217\u540d<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">column_type<\/td>\n<td style=\"text-align: left;\">\u5217\u7c7b\u578b<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">tbl_id<\/td>\n<td style=\"text-align: left;\">\u8868id<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">long_low_value<\/td>\n<td style=\"text-align: left;\">\u6574\u6570\u5217\u5b58\u50a8\u6574\u6570\u6700\u5c0f\u503c<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">long_high_value<\/td>\n<td style=\"text-align: left;\">\u6574\u6570\u5217\u5b58\u50a8\u6574\u6570\u6700\u5927\u503c<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">double_high_value<\/td>\n<td style=\"text-align: left;\">float\u5217\u5b58\u50a8float\u6700\u5c0f\u503c<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">double_low_value<\/td>\n<td style=\"text-align: left;\">float\u5217\u5b58\u50a8float\u6700\u5927\u503c<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">big_decimal_low_value<\/td>\n<td style=\"text-align: left;\">decimal\u5217\u5b58\u50a8decimal\u6700\u5c0f\u503c<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">big_decimal_high_value<\/td>\n<td style=\"text-align: left;\">decimal\u5217\u5b58\u50a8decimal\u6700\u5927\u503c<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">num_nulls<\/td>\n<td style=\"text-align: left;\">null\u7684\u6570\u76ee<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">num_distincts<\/td>\n<td style=\"text-align: left;\">distinct\u503c\u7684\u6570\u76ee<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">avg_col_len<\/td>\n<td style=\"text-align: left;\">string\u5217\u7684\u5e73\u5747\u5217\u957f\u5ea6<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">max_col_len<\/td>\n<td style=\"text-align: left;\">string\u5217\u7684\u6700\u5927\u5217\u957f\u5ea6<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">num_trues<\/td>\n<td style=\"text-align: left;\">boolean\u5217true\u7684\u6570\u76ee<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">num_falses<\/td>\n<td style=\"text-align: left;\">boolean\u5217false\u7684\u6570\u76ee<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">last_analyzed<\/td>\n<td style=\"text-align: left;\">\u6700\u540e\u7edf\u8ba1\u65f6\u95f4<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u6bd4\u5982\uff1a<\/p>\n<p><strong>\u6211\u60f3\u77e5\u9053emp\u5458\u5de5\u8868\u91cc\u9762\uff0c\u5458\u5de5\u7684\u6700\u9ad8\u85aa\u8d44\u548c\u6700\u4f4e\u85aa\u8d44\u662f\u591a\u5c11\uff1f<\/strong><\/p>\n<ul>\n<li><code>sal<\/code>\u5b57\u6bb5\u662f<code>int<\/code>\u7c7b\u578b\uff0c\u53ef\u4ee5\u53c2\u8003<code>long_low_value<\/code>\u548c<code>long_high_value<\/code> \u5b57\u6bb5\u83b7\u53d6\u5230\u6700\u5c0f\u503c\u548c\u6700\u5927\u503c\u3002\u3002<\/li>\n<\/ul>\n<p><strong>\u6211\u60f3\u77e5\u9053emp\u5458\u5de5\u8868\u91cc\u9762\uff0c\u6ca1\u6709<code>comm<\/code>\u5956\u91d1\u7684\u4eba\u6570\uff1f<\/strong><\/p>\n<ul>\n<li>\u53ef\u4ee5\u53c2\u8003<code>NUM_NULLS<\/code>\u5b57\u6bb5\u83b7\u53d6\u5230<code>sal<\/code>\u5217\u4e3anull\u7684\u6570\u91cf\u3002<\/li>\n<\/ul>\n<p><strong>\u6211\u60f3\u77e5\u9053emp\u5458\u5de5\u8868\u91cc\u9762\uff0c\u54ea\u4e00\u5217\u6570\u636e\u91cd\u590d\u503c\u8f83\u591a\uff1f<\/strong><\/p>\n<ul>\n<li>\u53ef\u4ee5\u53c2\u8003<code>num_distincts<\/code>\u5b57\u6bb5\u83b7\u53d6\u5230distinct\u503c\u7684\u6570\u76ee\uff0c\u503c\u8d8a\u5927\uff0c\u4ee3\u8868\u91cd\u590d\u7387\u8d8a\u4f4e\uff1b\u53cd\u4e4b\u8d8a\u9ad8\u3002<\/li>\n<\/ul>\n<p><strong>\u6211\u60f3\u77e5\u9053emp\u5458\u5de5\u8868\u91cc\u9762\uff0c\u5217\u957f\u5ea6\u7684\u6700\u5927\u503c\u548c\u5e73\u5747\u503c\uff1f<\/strong><\/p>\n<ul>\n<li>\u6ce8\u610f\uff0c<code>avg_col_len<\/code>\u548c<code>max_col_len<\/code>\u5217\u4ec5\u5bf9string\u7c7b\u578b\u7684\u5217\u6709\u6548\u3002<\/li>\n<\/ul>\n<p>\u8fd8\u6709\u5f88\u591a\u5176\u4ed6\u91cd\u8981\u7684\u7edf\u8ba1\u4fe1\u606f\u53ef\u4ee5\u4f9b\u5206\u6790\uff0c\u5f85\u5927\u5bb6\u6df1\u5165\u6316\u6398\u5176\u4e2d\u7684\u7528\u6cd5\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u6982\u8981\u63cf\u8ff0 \u672c\u6587\u4e3b\u8981\u4ecb\u7ecd\u5982\u4f55\u901a\u8fc7\u6536\u96c6\u8868\u7684\u5217\u7edf\u8ba1\u4fe1\u606f\uff0c\u5bf9TAB_COL_STATS\u7684\u7ed3\u679c\u8fdb\u884c\u5206\u6790\u3002 \u8be6\u7ec6\u8bf4\u660e \u9996\u5148 ..<\/p>\n<div class=\"clear-fix\"><\/div>\n<p><a href=\"https:\/\/kbwp.transwarp.cn\/?p=10683\" title=\"read more...\">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":[38],"tags":[],"class_list":["post-10683","post","type-post","status-publish","format-standard","hentry","category-configuration"],"acf":[],"_links":{"self":[{"href":"https:\/\/kbwp.transwarp.cn\/index.php?rest_route=\/wp\/v2\/posts\/10683","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=10683"}],"version-history":[{"count":1,"href":"https:\/\/kbwp.transwarp.cn\/index.php?rest_route=\/wp\/v2\/posts\/10683\/revisions"}],"predecessor-version":[{"id":10685,"href":"https:\/\/kbwp.transwarp.cn\/index.php?rest_route=\/wp\/v2\/posts\/10683\/revisions\/10685"}],"wp:attachment":[{"href":"https:\/\/kbwp.transwarp.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10683"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kbwp.transwarp.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10683"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kbwp.transwarp.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10683"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}