SQL Tutorial - 23: The LIKE Operator and Wildcard Characters Video Lecture | Microsoft SQL for Beginners - Database Management

hello guys what my channel this is the
twenty-third tutorial in this course and
in this video we'll be talking about the
like operator see you've seen the micro
creator once when we have the tutorial
on logical operators I mentioned it and
you also saw a couple of applications of
red in the MySQL environment but you
know I thought that there should be one
separately toriel on the like operator
and the wildcard characters are
associated with the like red and so
there is a and the like operator as you
guys know is used to compare our values
similar values in a table in the
database and what I mean by this is if
you have some value that you want to
place in your where clause
and you want to compare that value with
the values that are present in you know
your table in the database then you
would have to use a like credit to make
such comparisons and the like operator
is used with wildcard characters and
there are two wild-card characters that
you can use the first one is the
percentage symbol in the second one is
the underscore character the percentage
symbol is a substitution for zero one or
many characters whereas the underscore
character stands for one character
number and the syntax of the vibrator is
pretty simply part of select keyword
first and then Colin list and then drawn
keyword and the name of the table from
which you are putting your data and then
an optional weight loss through which
you would you know make the comparison
using the like operator right and even
if you are making comparisons between
numeric values you have to place your
values within single quotes and this is
different because when you use the
assignment operator to make direct
comparisons or record any test we do not
put our new values within single quotes
but we're using the like operator even
if you are making comparisons between
numbers you have to make sure that the
values that are there the word laws are
between single quotes and this would be
clear when we check out examples in the
mask environment so let's check out few
examples but got my workbench air and
just as we have in the past tutorials we
are going to work the employee table in
the test database and let me show you
guys the data that I have in the table
at the moment so to show the data I want
the executi select start worry name the
table is employee semicolon when I press
control enter I see that I have 17
records in the table the first row has
the value of the ID field as 1900 and
the last row has the value of 1967 total
there are 17 fees in the table and the
last record
well it wasn't present in the table till
this tutorial I added this row to this
table you know for the sake of this
result because I wanted one employee to
have this of an email account on hotmail
right and you understand why I did that
in just a minute so you know let's start
with this in fact you know suppose I
want to find out the you know name or in
fact all the information about the
employee who's got this of an email
address at hotmail then the query that
would be I'll type in select first right
and then I put in the ass example
because I want to pull out all
information and then the name of the
table after the strong keyword which is
employee and then type in where and then
since I want the comparison to be made
more with the value that's telling the
email field I'll type in email here
first right and then I type in the light
keyword because I would not be usually
like operator to make the comparison
between the value that's there in the Y
that I'm going to put within single
quotes and since you know I just want to
know you know who is got his or her
email address at hotmail I am NOT
concerned with the initial part of the
email address or the last part of the
email address and the last part I know
that after hotmail
we're going to have calm but you know
I'll just type in hotmail here and I
will put in a percentage character after
hotmail and and put in percentage
character for Hortman so what this is
going to do is it's going to instruct
SQL that get me all the records you
don't care what the first part of the
email addresses more the last part of
the email addresses we just want to make
sure that you know the word hot man is
there in the email address I put in a
semicolon at the end terminated
statement when I execute it I see that I
have purchased one employee in the table
who has you know his email address
registered at heart meds or the name of
the employees job and the IDS 19:16 is
the row that I added right and let's say
you want to also find out you know all
the employees who are in their twenties
right so since in this case we would be
working with the age column I would
replace men with age and you know since
you want to know employees were greater
than four years or in less than twenty
years old
we can use the or and logical operators
to you know generate this condition but
if you want to use the like greater than
what you do is within single quotes
important too and then you put an
underscore character after also the
underscore character as I mentioned when
you were looking through the PowerPoint
that the underscore character
substitutes one character number so in
this case it's a substitution for one
number so we don't care what the value
after two is if it's 21 or 22 or 23 or
29 but the first digit in the age has to
be two so as long as the first did it is
to you know the row is going to be
displayed in the result set
so when I execute this query I see that
all these employees have their age in 20
so John is 26 years old nick is 25 Dave
is 27 minus 21 so on and so forth and
the last example that we're going to
check out in this example we'll use the
underscore character as well as the
portion designee so suppose you want to
find out
you know information about employees you
know who have oh the alphabet Oh as the
second character in their names right so
it's obviously we work with the name
field and type in the like keyword and
then within single quotes the value
which I'm going to make my comparisons
is going to be I'd put in the underscore
characters first then the alphabet Co
and then we person date simply so what
this is going to do is it's going to
instruct SQL that the first character in
the name will be anything right it will
be BS
pee-eww whatever the second alphabet or
the second character has to be the
alphabet oh and the rest of the name
could also have as many characters or
you know whatever character so we are
not concerned about the last part of the
name or the first act of the name would
be concerned about the second alphabet
which has to be oh right I totally
semicolon when I execute this query I
see that I get all these names in the
result set so John you know you can see
that John's a name as low as I can
gagged Rogers name as also second
character Howard's name is always in
character so so on and so forth so
that's it about the dive operator I hope
you guys had fun watching this tutorial
and please subscribe to my channel in
case you have already and I'll see you
in the next tutorial