{"id":1020,"date":"2024-12-17T10:10:12","date_gmt":"2024-12-17T03:10:12","guid":{"rendered":"https:\/\/www.pgtutorial.com\/?page_id=1020"},"modified":"2025-01-05T19:54:14","modified_gmt":"2025-01-05T12:54:14","slug":"postgresql-var_samp","status":"publish","type":"page","link":"https:\/\/www.pgtutorial.com\/postgresql-aggregate-functions\/postgresql-var_samp\/","title":{"rendered":"PostgreSQL VAR_SAMP Aggregate Function"},"content":{"rendered":"\n<p><strong>Summary<\/strong>: in this tutorial, you&#8217;ll learn how to use the PostgreSQL <code>VAR_SAMP<\/code> aggregate function to calculate the sample variance of a set of values.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id='getting-started-with-the-postgresql-var_samp-aggregate-function'>Getting Started with the PostgreSQL VAR_SAMP aggregate function <a href=\"#getting-started-with-the-postgresql-var_samp-aggregate-function\" class=\"anchor\" id=\"getting-started-with-the-postgresql-var_samp-aggregate-function\" title=\"Anchor for Getting Started with the PostgreSQL VAR_SAMP aggregate function\">#<\/a><\/h2>\n\n\n\n<p>Given a set of values, a sample variance measures how much values differ from the average value or <em>mean<\/em>.<\/p>\n\n\n\n<p class=\"note\">In statistics, mean and average are the same concept.<\/p>\n\n\n\n<p>Sample variance is an important indicator because it reflects the spread or dispersion of the data points.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id='how-to-calculate-sample-variance'>How to Calculate Sample Variance <a href=\"#how-to-calculate-sample-variance\" class=\"anchor\" id=\"how-to-calculate-sample-variance\" title=\"Anchor for How to Calculate Sample Variance\">#<\/a><\/h3>\n\n\n\n<p>Here&#8217;s how you calculate the sample variance:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>First, calculate the mean of all the values.<\/li>\n\n\n\n<li>Next, subtract the mean from each value to find the difference (or deviation) of each value from the mean.<\/li>\n\n\n\n<li>Then, square each deviation to ensure all the values are positive.<\/li>\n\n\n\n<li>After that, sum all the squared deviations.<\/li>\n\n\n\n<li>Finally, divide the sum by the number of values minus one (n &#8211; 1) to get the sample variance.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id='formula-for-sample-variance'>Formula for Sample Variance <a href=\"#formula-for-sample-variance\" class=\"anchor\" id=\"formula-for-sample-variance\" title=\"Anchor for Formula for Sample Variance\">#<\/a><\/h3>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"340\" height=\"116\" src=\"https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2024\/12\/postgresql-var_samp-formula.png\" alt=\"postgresql var_samp formula\" class=\"wp-image-1022\" srcset=\"https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2024\/12\/postgresql-var_samp-formula.png 340w, https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2024\/12\/postgresql-var_samp-formula-300x102.png 300w\" sizes=\"auto, (max-width: 340px) 100vw, 340px\" \/><\/figure>\n\n\n\n<p>where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>s<sup>2<\/sup> is the sample variance.<\/li>\n\n\n\n<li>x<sub>i<\/sub> is each individual value.<\/li>\n\n\n\n<li>x\u0304 is the mean.<\/li>\n\n\n\n<li>n is the number of values in the sample.<\/li>\n<\/ul>\n\n\n\n<p>In PostgreSQL, you can use the <code>VAR_SAMP<\/code> aggregate function to calculate the sample variance of a set of values:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-1\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">SELECT<\/span> VAR_SAMP(column1)\n<span class=\"hljs-keyword\">FROM<\/span> <span class=\"hljs-built_in\">table_name<\/span>;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-1\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>In this syntax, the <code>VAR_SAMP<\/code> function takes all values in <code>column1<\/code> and returns the sample variance.<\/p>\n\n\n\n<p>The <code>VAR_SAMP<\/code> function ignores <code><a href=\"https:\/\/www.pgtutorial.com\/postgresql-tutorial\/postgresql-not-null\/\">NULL<\/a><\/code> in <code>column1<\/code>. It only uses non-NULL when calculating the sample variance.<\/p>\n\n\n\n<p>If <code>column1<\/code> has no value, i.e., no rows to aggregate, the <code>VAR_SAMP<\/code> function returns <code>NULL<\/code>.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id='calculating-sample-variance-for-groups'>Calculating Sample Variance for Groups <a href=\"#calculating-sample-variance-for-groups\" class=\"anchor\" id=\"calculating-sample-variance-for-groups\" title=\"Anchor for Calculating Sample Variance for Groups\">#<\/a><\/h3>\n\n\n\n<p>To calculate the sample variance for groups, you can use the <code>VAR_SAMP<\/code> function with the <code><a href=\"https:\/\/www.pgtutorial.com\/postgresql-tutorial\/postgresql-group-by\/\">GROUP BY<\/a><\/code> clause:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-2\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">SELECT<\/span> column2, VAR_SAMP(column1)\n<span class=\"hljs-keyword\">FROM<\/span> <span class=\"hljs-built_in\">table_name<\/span>\n<span class=\"hljs-keyword\">GROUP<\/span> <span class=\"hljs-keyword\">BY<\/span> column2;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-2\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>In this syntax:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>The <code><a href=\"https:\/\/www.pgtutorial.com\/postgresql-tutorial\/postgresql-group-by\/\">GROUP BY<\/a><\/code> clause divides the rows in the <code>table_name<\/code> by the values in <code>column2<\/code> into various groups.<\/li>\n\n\n\n<li>The <code>VAR_SAMP<\/code> function calculates the sample variance for values in each group.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id='postgresql-var_samp-aggregate-function-examples'>PostgreSQL VAR_SAMP Aggregate Function Examples <a href=\"#postgresql-var_samp-aggregate-function-examples\" class=\"anchor\" id=\"postgresql-var_samp-aggregate-function-examples\" title=\"Anchor for PostgreSQL VAR_SAMP Aggregate Function Examples\">#<\/a><\/h2>\n\n\n\n<p>Let&#8217;s explore using the <code>VAR_SAMP<\/code> function with practical examples based on an inventory database.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"159\" height=\"254\" src=\"https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2024\/12\/products.png\" alt=\"\" class=\"wp-image-1051\"\/><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\" id='calculating-the-sample-variance-of-product-weight'>Calculating the Sample Variance of Product Weight <a href=\"#calculating-the-sample-variance-of-product-weight\" class=\"anchor\" id=\"calculating-the-sample-variance-of-product-weight\" title=\"Anchor for Calculating the Sample Variance of Product Weight\">#<\/a><\/h3>\n\n\n\n<p>The following example uses the <code>VAR_SAMP<\/code> function to calculate the sample variance of weights for all products:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-3\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">SELECT<\/span>\n  VAR_SAMP(gross_weight) <span class=\"hljs-keyword\">AS<\/span> sample_variance\n<span class=\"hljs-keyword\">FROM<\/span>\n  products;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-3\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p><a href=\"https:\/\/www.pgtutorial.com\/playground\/?q=U0VMRUNUIFZBUl9TQU1QKGdyb3NzX3dlaWdodCkgQVMgc2FtcGxlX3ZhcmlhbmNlIEZST00gcHJvZHVjdHM7\" target=\"_blank\" rel=\"noreferrer noopener\">Try it<\/a><\/p>\n\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-4\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\">   sample_variance\n<span class=\"hljs-comment\">----------------------<\/span>\n <span class=\"hljs-number\">286.3391993333333333<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-4\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The output sample variance indicates how much the products&#8217; weights differ from the mean weight.<\/p>\n\n\n\n<p>To make the result more readable, you can round it using the <code>ROUND()<\/code> function:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-5\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">SELECT<\/span>\n  ROUND(VAR_SAMP(gross_weight),<span class=\"hljs-number\">2<\/span>) <span class=\"hljs-keyword\">AS<\/span> sample_variance\n<span class=\"hljs-keyword\">FROM<\/span>\n  products;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-5\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-6\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"> sample_variance\n<span class=\"hljs-comment\">-----------------<\/span>\n          <span class=\"hljs-number\">286.34<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-6\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h3 class=\"wp-block-heading\" id='calculating-the-sample-variance-of-product-weight-by-category'>Calculating the Sample Variance of Product Weight by Category <a href=\"#calculating-the-sample-variance-of-product-weight-by-category\" class=\"anchor\" id=\"calculating-the-sample-variance-of-product-weight-by-category\" title=\"Anchor for Calculating the Sample Variance of Product Weight by Category\">#<\/a><\/h3>\n\n\n\n<p>The following example uses the <code>VAR_SAMP<\/code> function with the <code>GROUP BY<\/code> clause to calculate the sample variance of product weights by category:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-7\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">SELECT<\/span>\n  category_id,\n  ROUND(VAR_SAMP(gross_weight), <span class=\"hljs-number\">5<\/span>) <span class=\"hljs-keyword\">AS<\/span> sample_variance\n<span class=\"hljs-keyword\">FROM<\/span>\n  products\n<span class=\"hljs-keyword\">GROUP<\/span> <span class=\"hljs-keyword\">BY<\/span>\n  category_id;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-7\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p><a href=\"https:\/\/www.pgtutorial.com\/playground\/?q=U0VMRUNUIGNhdGVnb3J5X2lkLCBST1VORChWQVJfU0FNUChncm9zc193ZWlnaHQpLCA1KSBBUyBzYW1wbGVfdmFyaWFuY2UgRlJPTSBwcm9kdWN0cyBHUk9VUCBCWSBjYXRlZ29yeV9pZDs%3D\" target=\"_blank\" rel=\"noreferrer noopener\">Try it<\/a><\/p>\n\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-8\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"> category_id | sample_variance\n<span class=\"hljs-comment\">-------------+-----------------<\/span>\n          <span class=\"hljs-number\">11<\/span> |         <span class=\"hljs-number\">0.38589<\/span>\n           <span class=\"hljs-number\">9<\/span> |        <span class=\"hljs-number\">65.78045<\/span>\n           <span class=\"hljs-number\">3<\/span> |         <span class=\"hljs-number\">0.00436<\/span>\n           <span class=\"hljs-number\">5<\/span> |         <span class=\"hljs-number\">0.00000<\/span>\n           <span class=\"hljs-number\">4<\/span> |         <span class=\"hljs-number\">0.05120<\/span>\n           <span class=\"hljs-number\">6<\/span> |         <span class=\"hljs-number\">0.00020<\/span>\n          <span class=\"hljs-number\">12<\/span> |        <span class=\"hljs-number\">29.79920<\/span>\n           <span class=\"hljs-number\">8<\/span> |        <span class=\"hljs-number\">32.41350<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-8\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>In this example:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>First, the <code>GROUP BY<\/code> clause divides the products by the <code>category_id<\/code> into groups.<\/li>\n\n\n\n<li>The <code>VAR_SAMP<\/code> function calculates the sample variance for gross weights in each group.<\/li>\n<\/ul>\n\n\n\n<p>If you want to retrieve the category name, you can join the <code>products<\/code> table with the <code>categories<\/code> table:<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"415\" height=\"254\" src=\"https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2024\/12\/products-categories-1.png\" alt=\"\" class=\"wp-image-1049\" srcset=\"https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2024\/12\/products-categories-1.png 415w, https:\/\/www.pgtutorial.com\/wp-content\/uploads\/2024\/12\/products-categories-1-300x184.png 300w\" sizes=\"auto, (max-width: 415px) 100vw, 415px\" \/><\/figure>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-9\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"><span class=\"hljs-keyword\">SELECT<\/span>\n  category_name,\n  ROUND(VAR_SAMP(gross_weight), <span class=\"hljs-number\">5<\/span>) <span class=\"hljs-keyword\">AS<\/span> sample_variance\n<span class=\"hljs-keyword\">FROM<\/span>\n  products\n  <span class=\"hljs-keyword\">JOIN<\/span> categories <span class=\"hljs-keyword\">USING<\/span> (category_id)\n<span class=\"hljs-keyword\">GROUP<\/span> <span class=\"hljs-keyword\">BY<\/span>\n  category_name;<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-9\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p><a href=\"https:\/\/www.pgtutorial.com\/playground\/?q=U0VMRUNUIGNhdGVnb3J5X25hbWUsIFJPVU5EKFZBUl9TQU1QKGdyb3NzX3dlaWdodCksIDUpIEFTIHNhbXBsZV92YXJpYW5jZSBGUk9NIHByb2R1Y3RzIEpPSU4gY2F0ZWdvcmllcyBVU0lORyAoY2F0ZWdvcnlfaWQpIEdST1VQIEJZIGNhdGVnb3J5X25hbWU7\" target=\"_blank\" rel=\"noreferrer noopener\">Try it<\/a><\/p>\n\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-10\" data-shcb-language-name=\"PostgreSQL SQL dialect and PL\/pgSQL\" data-shcb-language-slug=\"pgsql\"><span><code class=\"hljs language-pgsql\"> category_name | sample_variance\n<span class=\"hljs-comment\">---------------+-----------------<\/span>\n Desktops      |        <span class=\"hljs-number\">29.79920<\/span>\n Televisions   |        <span class=\"hljs-number\">32.41350<\/span>\n Accessories   |         <span class=\"hljs-number\">0.00000<\/span>\n Tablets       |         <span class=\"hljs-number\">0.05120<\/span>\n Wearables     |         <span class=\"hljs-number\">0.00020<\/span>\n Laptops       |         <span class=\"hljs-number\">0.38589<\/span>\n Smartphones   |         <span class=\"hljs-number\">0.00436<\/span>\n Audio Systems |        <span class=\"hljs-number\">65.78045<\/span><\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-10\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PostgreSQL SQL dialect and PL\/pgSQL<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">pgsql<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>The output shows the variability of product weights within each category. The categories with higher sample variance might have a broader range of product weights.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id='summary'>Summary <a href=\"#summary\" class=\"anchor\" id=\"summary\" title=\"Anchor for Summary\">#<\/a><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Use the PostgreSQL <code>VAR_SAMP<\/code> aggregate function to calculate the sample variance of a set of values.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id='quiz'>Quiz <a href=\"#quiz\" class=\"anchor\" id=\"quiz\" title=\"Anchor for Quiz\">#<\/a><\/h2>\n\n\n\n<iframe loading=\"lazy\"\n  name=\"quiz\"\n  src=\"\/quiz\/?quiz=var_samp\"\n  height=\"700\"\n  width=\"600\"\n  class=\"iframe\"\n><\/iframe>\n\n<div class=\"helpful-block-content\" data-title=\"\">\n\t<header>\n\t\t<div class=\"wth-question\">Was this tutorial helpful ?<\/div>\n\t\t<div class=\"wth-thumbs\">\n\t\t\t<button\n\t\t\t\tdata-post=\"1020\"\n\t\t\t\tdata-post-url=\"https:\/\/www.pgtutorial.com\/postgresql-aggregate-functions\/postgresql-var_samp\/\"\n\t\t\t\tdata-post-title=\"PostgreSQL VAR_SAMP Aggregate Function\"\n\t\t\t\tdata-response=\"1\"\n\t\t\t\tclass=\"wth-btn-rounded wth-yes-btn\"\n\t\t\t>\n\t\t\t\t<svg\n\t\t\t\t\txmlns=\"http:\/\/www.w3.org\/2000\/svg\"\n\t\t\t\t\tviewBox=\"0 0 24 24\"\n\t\t\t\t\tfill=\"none\"\n\t\t\t\t\tstroke=\"currentColor\"\n\t\t\t\t\tstroke-width=\"2\"\n\t\t\t\t\tstroke-linecap=\"round\"\n\t\t\t\t\tstroke-linejoin=\"round\"\n\t\t\t\t\tclass=\"feather feather-thumbs-up block w-full h-full\"\n\t\t\t\t>\n\t\t\t\t\t<path\n\t\t\t\t\t\td=\"M14 9V5a3 3 0 0 0-3-3l-4 9v11h11.28a2 2 0 0 0 2-1.7l1.38-9a2 2 0 0 0-2-2.3zM7 22H4a2 2 0 0 1-2-2v-7a2 2 0 0 1 2-2h3\"\n\t\t\t\t\t><\/path>\n\t\t\t\t<\/svg>\n\t\t\t\t<span class=\"sr-only\"> Yes <\/span>\n\t\t\t<\/button>\n\n\t\t\t<button\n\t\t\t\tdata-response=\"0\"\n\t\t\t\tdata-post=\"1020\"\n\t\t\t\tdata-post-url=\"https:\/\/www.pgtutorial.com\/postgresql-aggregate-functions\/postgresql-var_samp\/\"\n\t\t\t\tdata-post-title=\"PostgreSQL VAR_SAMP Aggregate Function\"\n\t\t\t\tclass=\"wth-btn-rounded wth-no-btn\"\n\t\t\t>\n\t\t\t\t<svg\n\t\t\t\t\txmlns=\"http:\/\/www.w3.org\/2000\/svg\"\n\t\t\t\t\tviewBox=\"0 0 24 24\"\n\t\t\t\t\tfill=\"none\"\n\t\t\t\t\tstroke=\"currentColor\"\n\t\t\t\t\tstroke-width=\"2\"\n\t\t\t\t\tstroke-linecap=\"round\"\n\t\t\t\t\tstroke-linejoin=\"round\"\n\t\t\t\t>\n\t\t\t\t\t<path\n\t\t\t\t\t\td=\"M10 15v4a3 3 0 0 0 3 3l4-9V2H5.72a2 2 0 0 0-2 1.7l-1.38 9a2 2 0 0 0 2 2.3zm7-13h2.67A2.31 2.31 0 0 1 22 4v7a2.31 2.31 0 0 1-2.33 2H17\"\n\t\t\t\t\t><\/path>\n\t\t\t\t<\/svg>\n\t\t\t\t<span class=\"sr-only\"> No <\/span>\n\t\t\t<\/button>\n\t\t<\/div>\n\t<\/header>\n\n\t<div class=\"wth-form hidden\">\n\t\t<div class=\"wth-form-wrapper\">\n\t\t\t<div class=\"wth-title\"><\/div>\n\t\t\t\n\t\t\t<textarea class=\"wth-message\"><\/textarea>\n\n\t\t\t<button class=\"btn btn-primary wth-btn-submit\">Send<\/button>\n\t\t\t<button class=\"btn wth-btn-cancel\">Cancel<\/button>\n\t\t\n\t\t<\/div>\n\t<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Summary: in this tutorial, you&#8217;ll learn how to use the PostgreSQL VAR_SAMP aggregate function to calculate the sample variance of a set of values. Getting Started with the PostgreSQL VAR_SAMP aggregate function # Given a set of values, a sample variance measures how much values differ from the average value or mean. In statistics, mean [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":950,"menu_order":7,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1020","page","type-page","status-publish","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.5 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>PostgreSQL VAR_SAMP Aggregate Function<\/title>\n<meta name=\"description\" content=\"In this tutorial, you&#039;ll learn how to use the PostgreSQL VAR_SAMP aggregate function to calculate the sample variance of a set of values.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.pgtutorial.com\/postgresql-aggregate-functions\/postgresql-var_samp\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta 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