MongoDB Tutorial for Beginners 6 - Query Document Video Lecture | The Complete Developers Guide to Mongo DB - Database Management

hello guys welcome to the next video on
MongoDB database tutorial for beginners
in the last video we have seen how we
can insert the data into the documents
in MongoDB now in this video we will see
how we can query the data from the
documents using MongoDB so in the last
video if you remember we have created a
database called school which we are
going to use in this video also so just
use school and then to query all the
documents from a collection which we
have created in the last video inside
school which was student what we can do
is we can just write DB dot the
collection name which is student in our
case and then just write find and then
give these two brackets something like
this okay and then execute this and it
gives all the data which we have
inserted into the student collection
which is these documents right now if
you can see here this is the dump of the
results and it's not pretty fide or it's
not shown in a pretty way so to show
this data in a pretty way we have a
command called pretty so just write dot
pretty okay and when you give this
command after this fine and the executed
you will see this data in a pretty fide
form or in you know just like JSON
format right and if you observe this
data which is given by this Mongo DB
query you can see this data and if you
remember last time we have inserted
these elements called student number
first name last name and age but there
is a extra field here added to our
output which is ID right so this is
because whenever we insert a document
mongodb it creates a unique ID for every
you know document so that on the basis
of this we can query our data because
this is the unique ID for your document
now if you're if you give this ID by
yourself for example you give the side
is equal to one or two or any other ID
then it's going to show you this ID
otherwise MongoDB is going to create a
ID by itself for you which is shown to
you here okay
now whenever you you know vary the
database there can be some condition on
the basis of those condition you want to
query the data for example I want to
query the data only for student one okay
now the first way of you know querying
the first document from your document
list is just go here and just write DB
dot students and then dot find and then
you have this option called find one
okay and this option is going to give
you the first document so when we
execute this query it gives the first
document which was inserted in this
database okay now there are some
condition on the basis of which you want
to query the database for example you
want to query the database on the basis
of age or for example we want to query
the database on the basis of student
number and we want the data of the
student whose number is two for example
so what we can do is we can just write
on the next line DB dot student dot find
once again and then give these two round
brackets and inside these two round
bracket just give these curly brackets
and then
give the you know whatever element you
want to co Eric query okay so for
example I want to just query the student
number inside these curly brackets I
will just write in double quotes student
number and then is equal to two or : 2
and keep in mind we need to give double
quotes here because here also we have
given the double quotes right and then
just select all the command and execute
it and now it gives the data for student
2 you can see here okay now for example
you want to query the database on the
waist basis of age and we want the list
of all the document which is greater
than for example 16 year old okay so we
can just write instead of this we can
write age here and then we can just
write in the curly braces so just write
these curly braces and then give this
dollar symbol and then you just need to
write GT for greater then okay and then
give this colon here and then give the
number or the age which you want to
write here okay so for example we want
all the student which is greater than 15
years old okay and then we can just
execute this command and you can see all
the data age is more than 15 here okay
and there is one more command for
example you want to show the stood and
who are more than fifteen including 15
so greater than or equal to so you just
write GT and just include letter e here
which sent for equality so it will show
you the data which is greater than or
equal to 15 so let's execute this
command and you can see 15 is included
here
in the same way we have less than
command so instead of gt/e we can just
write L T which is less than okay
and let's execute this command and it
gives a result all the ages which is
less than 15 so 13 12 and 10 and in the
same way as greater than you can just
add letter e here which includes the
Equality for this command so whenever we
execute this command it gives or it
includes the 15 year old student also
because it's equal to less than or equal
to okay now there is one last command
which is there which is called not equal
to and for that you just need to write n
e here so any stand for naught equals
okay so it will give the data for all
the student which is not equal to 15
year-old
okay so just execute this command and it
gives all the edges except 15 okay and
for example you want to prettify this
result once again you can just right
here pretty okay so you can just add
this command or add this function here
and then execute this command once again
and gives you the result in a pretty
fide way so in this way you can vary
your documents there are more ways of
acquiring your documents which I will
show you in the next video so please
rate comment and subscribe and bye for
now