SQL query in wp_postmeta table

Question

How to make an SQL query in a table that has the following fields:

SELECT meta_key,meta_value from wp_postmeta where meta_key = 'cidade' and meta_key = 'bairro'

the fields of the table wp_postmeta field meta_key = 'City' and meta_value = 'Curitiba' and meta_key = 'neighborhood' and meta_value = 'Center' is the following I want to make a select when I select a city in the other select it shows only the neighborhoods related to the city that was selected then I want to know if you can do this, if there is how I do this relationship in sql?

Answer 1

Your query seems to be correct, but stay tuned to the base name. In Wordpress (which I assume you are using), the table name is wp_postmeta and not wp_postpostmeta.

In a more comprehensive case, a simple select meta_key, meta_value from wp_postmeta returns all occurrences of the two fields

EDIT

Your appointment isn’t quite right, at least for me. Are you searching all cities and all neighborhoods, or all neighborhoods of a city? In Wordpress logic, meta_key determines the field name, while meta_value, your value. Therefore, you would have meta_key = 'Cidade' and meta_value = 'Curitiba', for example. IN THIS CASE (i.e., if this is your logic), to select all the cities in your relationship, your query would be:

SELECT meta_key, meta_value FROM wp_postmeta WHERE meta_key='Cidade'

So you’d get returns like

meta_key | meta_value 
Cidade   | Curitiba
Cidade   | São Paulo

If, on the other hand, your meta_key be the NAME of the city, and the meta_value the NAME of the neighborhood, the consultation

SELECT meta_key, meta_value FROM wp_postmeta WHERE meta_key='São Paulo'

Could return:

meta_key  | meta_value 
São Paulo | Morumbi
São Paulo | Jabaquara

If this last logic which I have represented is the one which you are following (i.e., meta_key = 'nome_da_cidade'), and you want to list all the neighborhoods of all cities (again, I’m assuming things here), do:

SELECT meta_key, meta_value FROM wp_postmeta ORDER BY meta_key

I drew my conclusions based on your question. See if I am correct and let me know

Answer 2

SELECT meta_key,meta_value FROM wp_postpostmeta WHERE meta_key = 'cidade' OR meta_key = 'bairro'

Answer 3

The problem with your query is that you are using the and between the two conditions. This way, the bank will understand that it should return the fields meta_key and meta_value of all lines containing the meta_key value of 'city' and 'neighborhood', but there is no meta_key contain two different values on the same line.

To fix, you must use the operator or, whereas in your logic you want the bank to return the columns of the records that have the meta_key value of 'city' or 'neighborhood'.

SELECT meta_key,meta_value from wp_postpostmeta where (meta_key = 'cidade' OR meta_key = 'bairro')