{"id":5340,"date":"2026-01-19T17:02:14","date_gmt":"2026-01-19T16:02:14","guid":{"rendered":"https:\/\/sutilweb.eu\/?page_id=5340"},"modified":"2026-01-19T17:02:14","modified_gmt":"2026-01-19T16:02:14","slug":"46-funciones-mysql","status":"publish","type":"page","link":"https:\/\/sutilweb.eu\/index.php\/lenguajes\/php\/php-practico\/46-funciones-mysql\/","title":{"rendered":"46. Funciones MySQL"},"content":{"rendered":"\n<p>En este cap\u00edtulo vamos a ver algunas funciones que proporciona <strong>MySQL<\/strong> muy \u00fatiles a la hora de hacer consultas.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong><em>CONCAT(nombre, \u00bb \u00ab, apellidos) AS nombre_completo<\/em><\/strong>:\u00a0 mostrar\u00e1 el nombre y apellido en un s\u00f3lo campo separados por un espacio en blanco bajo el alias <strong><em>nombre_completo<\/em><\/strong>.<\/li>\n\n\n\n<li><strong><em>CONCAT_WS(\u00bb \u00ab, nombre, apellidos) AS nombre_completo<\/em><\/strong>: mostrar\u00e1 el nombre y apellido en un s\u00f3lo campo, separados por un espacio en blanco en nuestro caso, que se pasa como primer par\u00e1metro.<\/li>\n\n\n\n<li><strong><em>LENGTH(nombre) AS \u00abLongitud Nombre\u00bb<\/em><\/strong>: muestra la longitud en este caso del campo nombre y d\u00e1ndole un nuevo nombre al campo cuyo valor es <strong><em>Longitud Nombre<\/em><\/strong>.<\/li>\n\n\n\n<li><strong><em>LOWER(CONCAT(nombre, \u00bb \u00ab, apellido)) AS nombre_completo<\/em><\/strong>: mostrar\u00e1 el texto en min\u00fasculas.<\/li>\n\n\n\n<li><strong><em>UPPER(CONCAT(nombre, \u00bb \u00ab, apellido)) AS nombre_completo<\/em><\/strong>: mostrar\u00e1 el texto en may\u00fasculas.<\/li>\n\n\n\n<li><strong><em>SELECT nombre, apellidos REPLACE(correo, \u00ab@gmail.com\u00bb, \u00ab@hotmail.com\u00bb) FROM contactos<\/em><\/strong>: a la hora de recuperar todos los registros pero en el campo correo, el <strong><em>@gmail.com<\/em><\/strong> lo va a reemplazar por <strong><em>@hotmail.com<\/em><\/strong>. Esta funci\u00f3n no modifica los datos que tengamos en la base de datos.<\/li>\n\n\n\n<li><strong><em>SELECT TRIM(nombre, apellidos) FROM contactos<\/em><\/strong>: elimina los espacios anteriores y posteriores a los datos que se encuentran en los campos <strong><em>nombre<\/em><\/strong> y <strong><em>apellidos <\/em><\/strong>de la tabla <strong><em>contactos<\/em><\/strong>. Verifica si hay espacios en blanco a la izquierda y a la derecha y de ser as\u00ed los elimina.<\/li>\n\n\n\n<li><strong><em>SELECT nombre, apellidos DATE_FORMAT(fecha_nacimiento, \u00ab%d\/%m\/%Y\u00bb) FROM contactos<\/em><\/strong>: esta funci\u00f3n espera que le pasemos dos par\u00e1metros, el primero es el campo y como segundo par\u00e1metro el formato como nosotros lo queremos. Importante utilizar el caracter porcentaje para que funcione.<\/li>\n\n\n\n<li><strong><em>SELECT nombre, apellidos, DAY(fecha_nacimiento) FROM contactos<\/em><\/strong>: devuelve el d\u00eda de la fecha de nacimiento.<\/li>\n\n\n\n<li><strong><em>SELECT nombre, apellidos, MONTH(fecha_nacimiento) FROM contactos<\/em><\/strong>: devuelve el mes de la fecha de nacimiento.<\/li>\n\n\n\n<li><strong><em>SELECT nombre, apellidos, YEAR(fecha_nacimiento) FROM contactos<\/em><\/strong>: devuelve el a\u00f1o de la fecha de nacimiento.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>En este cap\u00edtulo vamos a ver algunas funciones que proporciona MySQL muy \u00fatiles a la hora de hacer consultas.<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":4518,"menu_order":45,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center 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