Tutorial 9- Logical Operators Video Lecture | Postgresql: A Complete Tutorial - Database Management

hello guys welcome to our tutorial of
PostgreSQL today we are going to talk
about the logical operators so as you
could see that I have selected all the
record from my table company so you
could see the records so the role of
logical operator is basically to create
complex queries and to any bill
filtering in our data so the various
logical operators that we are going to
talk about it is the and operator the or
operator the is null operator the like
operator the in operator and the between
operator so we will start off by
discussing about the and operator to the
role of an and operator is to filter out
data when we have more than one
condition and we want both of them to be
true for example I will show you by show
an example that is select star from
company where age should be greater than
33 and salary should be greater than or
thousand rupees so I want these
conditions to be true that I want age to
be greater than 33 and I also want that
salary should be greater than thousand
or you could make it 2000 so I see the
filter out result that is age is greater
than 33 and salary is greater than 2000
rupees
so here the both conditions would be
true
so the second operator that we are going
to talk about is the or operator so in
the or operator we have this thing that
either of the condition should be true
like if we use the same query you could
use it by the up key and we place an R
so either this condition should be true
or either this should condition should
be true so if we apply is you see we get
these conditions so here the salary is
either greater than 2000 or it is or the
ages either greater than 33 so the next
operator that when we talk about is the
is null operator that is to represent
the null fields in our database that is
if you see that I have two fields that
are null in salary so to select those
fields I have to use select star from
company where salary is null so you
could see that I get two results where
the salary field is null the next
operator that is talked about is the
like operator so like operators
basically used to filter out the results
where a particular field is like a
particular query that you send that is
suppose select star from company their
name like like suppose I want the name
to begin with P so I want the name to
begin with P so I will write P and a
percentile ap means it should start from
P and percentile means anything could
follow up like it could be Priya
or it could be pre on she anything like
it the first one should be P and after
that it could be anything so you can see
that I get three on she and Priya in
this so it is used to filter out the
result by a string value so for example
I want a name to be ending with a so I
will use percent I a that means anything
could proceed a and the last one should
be a so you see I get two people whose
name end with a similarly I want people
whose name it includes a in anywhere so
I may use percentile a and again
percentile so it means that is a
anywhere so as you see I get these
results again
so this is all about the light query so
the next operator waving learn about is
the in in is basically to select a
particular value in that we define that
is suppose select star from company
where H in 20 just don't forget to put
these in single quotes 34 and 40 so if
you want to supply some values like
suppose we want the age to be in these
particular domains like 20 34 and 40 so
we use in query in operator so as you
can see this will return today the d-10
returned the results where age is either
20 or 30 4 or 40 so as you can see that
I am return with only those things so
this is the use of the in operator the
next operator is the between operator
always remember that between operator is
used with the and operator so it is
going to give us a set of results from a
range range of results from initial
value and a final value so you could see
that I will use this in their age
suppose between 23 and 34 so this will
give me the result between 23 and 34
remember 23 and 34 will be included in
this result so yeah as you could see I
get these results so this was all for
the logical operators thank you for
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