MySQL Database Tutorial - 10 - Basic Data Filtering and WHERE Video Lecture | MySQL (Sequential Query Language) Database Tutorial - Software Development

alright guys welcome to your tenth MySQL
tutorial in in this tutorial we're going
to learn about the basics of filtering
now we already learned kind of the
basics of filtering because we can now
limit our data well that's nice and all
but sometimes we just want to be able to
filter it a little bit more so let me go
ahead and show you guys a quick example
of say we want to select the ID and the
name of our customers so of course
customers but we only want to select the
person with the ID number of 54 so we go
ahead and write where ID equals 54 so
basically what this where Clause is is
basically saying okay we don't want all
the data we only want the data to be
filtered and after you give it kind of a
condition the first condition is just
this equal sign you write the name of
the column and then you write what you
want the results to be equal to and
since look oh I just bit my freaking
tongue since there's only one person
with the ID of 54 it returns one result
the person with ID and name ID being 54
now I told you guys that there were
several different conditions one of
those being the equal sign there's also
the not equal sign so if you want to say
something like with the ID not equal to
54 you can go ahead and do that and
another thing you can go ahead and write
a space between the equals and the
values and the columns you can either
have it like this or excuse me
accidentally deleted the wrong thing
like this or you can have a space I
usually switch it up a bit depending on
what I'm doing but I just want to
mention that again it goes back to that
whitespace rule so whenever I were to
run this test it would return all the
results however if we take a look you
see that 54 is excluded from the result
set that's because we said okay give me
all the results where the ID is not
equal to 54 now there are a couple other
tests that I'm going to just go and talk
to you guys about real quick you can
also have the less than sign so if you
say okay where ID is less than 8 or
something like that go ahead and hit go
and now you can see there are 7 people 1
2 3 4 5 6 7
have an ID of less than eight there's
also a variation of this it's a less
than equals and what this means is you
know how this result set ended at seven
if we go ahead and run this query right
here as you can see it includes eight so
less than or equal signs means is it
less than or equal to the value of eight
and that is what I want to be in another
thing I'm not going to show you guys a
test but there's also the greater than
or greater than equals two I don't think
I need to show you guys that test
because it's pretty self-explanatory
however there is one other test that I
want to show you guys and that is the
between test so where I D is between and
you give it two values the first value
I'll say is 25 and the second value is
30 you may be thinking that you may use
a comma for this value actually need
another keyword called and so this is
kind of a weird test it's not like an
equal sign or a less than sign you
actually need some key words and what
this is going to do is it's going to
return all the data where the ID or this
value is between this in this so
remember whenever you use the keyword
between you need two values using the +
sign so of course 2530 there you go just
as expecting now the last thing I want
to touch on on this tutorial is so far
we only worked with ID which is numbers
but what happens whenever we want to
work with text or characters well let me
go ahead and select the name and the
state from customers where state you
can't go ahead and write something like
this where state is equal to California
because if you do it's going to think
that California is either you know a
MySQL keyword that it doesn't understand
or maybe a name of a table or a column
so whenever you are working with where
clauses and the value is texts or
letters you need to surround it with
single quotation marks now whenever we
run this notice that CA is surrounded by
single quotation marks and you go ahead
and run this it returns it basically
whenever you surround something with
quotation marks it treats it as value
you instead of a keyword or column name
so now as you can see it returns all the
rows where the state is equal to
California
pretty cool huh so there you go there
you have it hopefully you guys
understand the beginning about filtering
data and all the different tests that
you can do not much to it but uh there's
a little bit more that we haven't
touched on yet some advanced filtering
and we're going to be covering that in
the next tutorial so thank you guys for
watching don't forget to subscribe and
I'll see you guys then