{"id":6004,"date":"2013-06-09T20:13:52","date_gmt":"2013-06-09T20:13:52","guid":{"rendered":"https:\/\/www.jose-aguilar.com\/blog\/?p=6004"},"modified":"2014-06-10T20:05:32","modified_gmt":"2014-06-10T20:05:32","slug":"mostrar-las-columnas-de-una-tabla-de-una-base-de-datos","status":"publish","type":"post","link":"https:\/\/www.jose-aguilar.com\/blog\/mostrar-las-columnas-de-una-tabla-de-una-base-de-datos\/","title":{"rendered":"Mostrar las columnas de una tabla de una base de datos"},"content":{"rendered":"<p>Para seg\u00fan que aplicaciones a veces nos interesar\u00eda mostrar las columnas o tuplas de una tabla de una base de datos. Me refiero a los nombres de los campos.<\/p>\n<p>Existe una consulta SQL que te muestra los nombres de los campos de una tabla, los tipos de datos, si se trata de una clave primaria, entre otros valores. Si ejecutas la siguiente consulta sobre una base de datos:<\/p>\n<pre><code>SHOW COLUMNS FROM YOUR_TABLE<\/code><\/pre>\n<p>Te dar\u00e1 como resultado algo como lo siguiente:<\/p>\n<p><a href=\"https:\/\/www.jose-aguilar.com\/blog\/wp-content\/uploads\/2013\/06\/fields.png\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-6005\" src=\"https:\/\/www.jose-aguilar.com\/blog\/wp-content\/uploads\/2013\/06\/fields.png\" alt=\"fields\" width=\"379\" height=\"317\" srcset=\"https:\/\/www.jose-aguilar.com\/blog\/wp-content\/uploads\/2013\/06\/fields.png 379w, https:\/\/www.jose-aguilar.com\/blog\/wp-content\/uploads\/2013\/06\/fields-300x250.png 300w\" sizes=\"auto, (max-width: 379px) 100vw, 379px\" \/><\/a><\/p>\n<p>Como puedes observar, te retorna los fields o campos de la tabla, el tipo de dato, null, key, Default y Extra.<\/p>\n<p>Esta query tambi\u00e9n la podemos llamar desde un script como una query cualquiera. Veremos como hacerlo con PHP y MySQLi:<\/p>\n<pre>&lt;?php\r\n$result = $conexion-&gt;query(\"SHOW COLUMNS FROM `clientes`\");\r\nif ($result-&gt;num_rows &gt; 0) {\r\n\u00a0\u00a0\u00a0 while ($row = $result-&gt;fetch_assoc()) {\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 echo $row['Field'].'&lt;br\/&gt;';\r\n\u00a0\u00a0\u00a0 }\r\n}\r\n?&gt;<\/pre>\n<p>Este peque\u00f1o script imprime por pantalla todos los campos de la tabla \u00abclientes\u00bb.<\/p>\n<p>Para que este mini script funcione har\u00e1 falta conectar con la base de datos previamente:<\/p>\n<pre>$conexion = new mysqli(DB_SERVER, DB_SERVER_USERNAME, DB_SERVER_PASSWORD, DB_DATABASE);<\/pre>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Para seg\u00fan que aplicaciones a veces nos interesar\u00eda mostrar las columnas o tuplas de una tabla de una base de datos. Me refiero a los nombres de los campos. Existe una consulta SQL que te muestra los nombres de los campos de una tabla, los tipos de datos, si se trata de una clave primaria, [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":6005,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[18,3],"tags":[],"class_list":["post-6004","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-mysql","category-php"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v25.6 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Mostrar las columnas de una tabla de una base de datos - Jose Aguilar Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<meta property=\"og:locale\" content=\"es_ES\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Mostrar las columnas de una tabla de una base de datos - Jose Aguilar Blog\" \/>\n<meta property=\"og:description\" content=\"Para seg\u00fan que aplicaciones a veces nos interesar\u00eda mostrar las columnas o tuplas de una tabla de una base de datos. Me refiero a los nombres de los campos. 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