Explicación del operador de comparación de meta_query

Losprimerosfuncionan comoera deesperar:

 =   equals
!=  does not equal
>   greater than
>=  greater than or equal to
<   less than
<=  less than or equal to
 

ME GUSTA y NO ME GUSTA

LIKE y NOT LIKE son operadores SQL que lepermiten agregar símbolos comodín,por lo quepodríatener unameta consulta que se vea así:

 array( 
    'key' => 'name', 
    'value' => 'Pat', 
    'compare' => 'LIKE'
)
 

Esto devolveríatodas laspublicaciones dondeel valormeta "nombre"tiene la cadena "Pat". Eneste caso,"Pat","Patricia" y "Patrick" le serán devueltos. Hay unaexplicación deltutorial quenoes de WordPress aquí .

Noesnecesario agregarel carácter comodín %,porque se agrega deformapredeterminada como @Herb dijoen su siguiente respuesta . Así: $meta_value = '%' . like_escape( $meta_value ) . '%';: consulte fuente .

EN y NO EN

IN y NOT IN seleccionan cualquier coincidencia queestéen (ono) lamatriz dada. Entoncespodrías hacer algo comoesto:

 array(
    'key'     => 'color', 
    'value'   => array('red', 'green', 'blue') 
    'compare' => 'IN'
)
 

y obtendríatodas laspublicaciones quetenganel colorestablecidoen rojo,verde o azul. El uso de 'NOT IN' obtiene lo contrario,cualquierpublicación quetenga un valorestablecidoen cualquier otra cosa queno sea lo queestáen lamatriz.

El SQLgeneradoparaesto se vería así:

 SELECT * FROM posts_meta WHERE value IN ("red", "green", "blue") 
 

ENTRE y NO ENTRE

BETWEEN y NOT BETWEENte permiten definir un rango de valores quepodrían ser correctos y requieren queproporciones dos valoresen unamatrizen tumeta_query:

 array( 
    'key' => 'price', 
    'value' => array(20,30) 
    'compare' => 'BETWEEN'
)
 

Esto le darátodas laspublicaciones dondeelprecioestéentre 20 y 30. Estapersona profundizaen unejemplo confechas.

NO EXISTE

NOT EXISTSesexactamente como suena:el valormetanoestáestablecido oestáestablecidoen un valornulo. Todo lo quenecesitaparaesa consultaesel operador clave y de comparación:

 array( 
    'key' => 'price', 
    'compare' => 'NOT EXISTS'
)
 

Estapersona necesitaba realizar una consultano valoresmetaexistentes,y losnecesitabaparajugarbien con los demás.

¡Espero queestote ayude!

The first several work as you would expect:

=   equals
!=  does not equal
>   greater than
>=  greater than or equal to
<   less than
<=  less than or equal to

LIKE and NOT LIKE

LIKE and NOT LIKE are SQL operators that let you add in wild-card symbols, so you could have a meta query that looks like this:

array( 
    'key' => 'name', 
    'value' => 'Pat', 
    'compare' => 'LIKE'
)

This would return all posts where the meta value "name" has the string "Pat". In this case, "Pat" "Patricia" and "Patrick" would all be returned back to you. There's a non-WordPress tutorial explanation here.

Adding the wildcard character % isn't necessary, because it gets added by default like @Herb said in his below answer. Like this: $meta_value = '%' . like_escape( $meta_value ) . '%'; - see source.

IN and NOT IN

IN and NOT IN select any matches that are in (or not in) the given array. So you could do something like this:

array(
    'key'     => 'color', 
    'value'   => array('red', 'green', 'blue') 
    'compare' => 'IN'
)

and it would get all posts that have the color set to either red, green, or blue. Using 'NOT IN' gets the reverse, any posts that have a value set to anything else than what's in the array.

The generated SQL for this would look something like this:

SELECT * FROM posts_meta WHERE value IN ("red", "green", "blue") 

BETWEEN and NOT BETWEEN

BETWEEN and NOT BETWEEN allow you to define a range of values that could be correct, and require you to give two values in an array in your meta_query:

array( 
    'key' => 'price', 
    'value' => array(20,30) 
    'compare' => 'BETWEEN'
)

This will get you all posts where the price is between 20 and 30. This person digs into an example with dates.

NOT EXISTS

NOT EXISTS is just like what it sounds - the meta value isn't set or is set to a null value. All you need for that query is the key and comparison operator:

array( 
    'key' => 'price', 
    'compare' => 'NOT EXISTS'
)

This person needed to query non-existent meta values, and needed them to play nice with others.

Hope this helps!

Tengaen cuenta que cuando se utiliza un valormeta_compare de 'LIKE',WordPressenvuelve automáticamenteel carácter comodín (%) alrededor de la cadenameta_value.Por lotanto,elejemplo 'Pat%'podríano devolverningún resultado.

Note that when using a meta_compare value of 'LIKE', WordPress automatically wraps the wildcard character ( % ) around the meta_value string. So the 'Pat%' example could fail to return any results.