MySQL Database Tutorial - 13 - How Search Engines Work Video Lecture | MySQL (Sequential Query Language) Database Tutorial - Software Development

what is going on guys welcome to your
13th MySQL tutorial and in this tutorial
I want to talk to you guys about
something called a wildcards now
wildcards are basically special symbols
that you could use to make your
filtering more advanced it's also what
search engines use whenever they use
MySQL to kind of like I said make your
search more smart more advanced because
whenever you type a dog or something in
Google it just doesn't give you the
results of dog it gives you dog house
dog bones dog food and like I said this
is I don't know I'm you know I'm just
gonna shut up and give you guys an
example but before I do I want to
mention this that customer table was you
know it was pretty cool for a few
examples but it could get a little stale
after a while so what I did is I
pretended that we would make a website
like eBay or Amazon comm and I made a
whole list of pretty much a bunch of
items now each of these items have an ID
which is just one two three four five
just a primary key so we can identify it
a name such as brand new I might
computer or you know a bed a stove
whatever actually had someone else fill
these in a cost which is the price of it
a seller ID which is whoever is selling
this item that's their ID number not
very important for this tutorial and the
number of bids on this item so this
would be like a website like eBay and
again if you guys want this table want
to practice follow along with me then
just go ahead and download that file
again and this items table is going to
be there whenever you import your file
so anyways with that long intro let me
go ahead and show you guys a quick wild
card example now let's go ahead and say
we wanted to search for items that
started with the keyword new like a new
dog or a new computer so what would you
do is write select name because remember
name is the name of the items like you
know carpet or brand new iMac computer
select name from items items is a table
remember where the name of the item is
alike now whenever you use like you can
go ahead
use something like this new % now this %
is pretty much the heart of this
tutorial this is the wild card and
there's also another underscore wild
card and I'll be talking that about that
in a second but what % means is
basically it means anything so if
something starts with the new such as
new computer that % could be a computer
if it's new house new computer or I
already said computer new sweater new
pair of jeans this wild card can mean
anything so let me go ahead and run this
query and see what we get
ok new gym socks new iPad stolen from
Best Buy new curtain from bedroom it
even can be a word or text after it so
like I said that % can either have
spaces basically we're saying if
anything starts with the word new then
go ahead and return that in the result
set
pretty cool huh so you may be thinking
ok if I go ahead and look at this items
table I see brand new iMac computer how
come that was in the result set
well that is because whenever we are in
our query we said ok this is like saying
it needs to start with the word new and
then anything after it doesn't matter
what's after it so what if we wanted to
you know maybe search for the word
computer but we didn't want to search
like computer desk computer chair we
wanted something like brand new computer
chair or something so it doesn't matter
what was before it or after it well what
we would need to do is put two percent
signs one before the word one after it
so now when we search your computer then
it doesn't matter what is before or
after a computer as long as computer is
somewhere in that name then check it out
a brand new iMac computer this is at the
end awesome alien computer game this is
in the middle super computer at the end
with no space in computer at the
beginning or the end depending on how
you look at it so basically remember
whenever you use this percent is a wild
card filter it means that do you want
anything to come before it or after it
and if you do just go ahead and put it
wherever you want now there's one other
way that you can use that wildcard
filter and that is having something
weird like putting it in the middle of
your term now whenever you put it in the
middle of your term then you must match
the first and last character but the
middle can be anything you want so let
me go ahead and select the city from I'm
gonna use the old table customers in
remember that's the table that we've
been using where the city name is like
and instead of using it instead of using
that wildcard before or after I'm gonna
use it in the middle so any city that
starts with H and ends with D it can be
anything can be any name no matter what
the length as long as it starts with H
and ends with D then we're gonna go
ahead and get those results so let me go
ahead and hit go and check it out
Hollywood Highland it doesn't matter the
only thing that matters is it starts
with H and ends with D what's in between
those two doesn't really matter and I
want to point out one other thing as you
notice I put a lowercase H here but it's
searched uppercase H and that's because
like I said my SQ o is not
case-sensitive the only reason that we
like to use uppercase from lower case is
it just makes it easier to read whenever
we're programming so we can quickly see
what's mysql and what are basically
whatever we created so even though we're
searching for H D this can be uppercase
or lowercase like I said my SQL is not
case-sensitive so that's why we got the
results Hollywood in Highland so there
are other wildcards that I want to talk
about and I also want to talk about
something called regular expressions but
I don't have time in this tutorial so I
guess you guys are just gonna have to
wait to the next video so thank guys for
watching don't forget to subscribe and
I'll see you guys then