How do I get all the data stored in the database from a specific month: I think you should pass the year / month as a parameter, for example, variable="2016/10"; remembering that the type of the data in the database and timestamp
SELECT * FROM dados WHERE data_registro = variavel
Option 1: Using TO_CHAR :
select * from dados where TO_CHAR(data_registro, 'MM/YYYY') = '01/2016'
Option 2: Use with ranges:
select * from dados where data_registro >= '2016-01-01'::DATE
and data_registro <= '2016-01-31'::DATE
Option 3: Using overlaps
select * from dados where (data_registro, data_registro)
OVERLAPS ('2016-01-01'::DATE, '2016-01-31'::DATE);
Option 4: With Extract :
select * from dados
where
Extract(month from data_registro) >= Extract(month from '2016-01-01'::DATE)
and Extract(month from data_registro) <= Extract(month from '2016-01-31'::DATE)
Option 5: Use of intervals based on current date:
SELECT *
FROM dados
WHERE Extract(month from data_registro) >= Extract(month from Now())
AND Extract(month from data_registro) <= Extract(month from Now() + Interval '20 day')
Just giving continuity to the options already mentioned
Option with date_trunc
SELECT * FROM dados WHERE
date_trunc('month', data_registro) = date_trunc('month', '2015-03-01');
In this case the parameter can be any valid date in the month, it will truncate both for the same month.
You can use BETWEEN :
SELECT dados
FROM tabela
WHERE tabela.data BETWEEN '2016-01-01' AND '2016-01-31'
If the field in question is a TIMESTAMP type, depending on your BD, you should remember to do CAST (eg Postgres tabela.data::DATE )