How to fetch the data from mysql in php
PHP Tutorial (& MySQL) #26 - Getting Data From a Database
Timecodes:
alright then so we've made our
connection to the database now how about
we try to actually retrieve some data
from it so we do that by issuing SQL or
sequel commands or otherwise called
queries ok now there's three steps to
making these queries sending them and
getting the data and it basically just
sent them first of all we construct the
query ok then we make the query and then
we fetch the results from that query so
there the three steps that we need to
perform so first of all let's actually
write the query to get all the pizzas so
let's do a little comment right here and
I'm gonna say write query for all pizzas
okay so I'm gonna store this query that
we construct in a variable and I'm going
to call it sequel or SQL and we're gonna
set that equal to a string and this is
where we're going to write our SQL now
you may have seen this before it's a lot
of capital letters with different
commands so what we're going to do is
use the Select command right there and
that is select data that's what it means
go and get data now I'm going to use
this start in fact what I'm gonna do is
write this out and then I'll explain it
so select star from pizzas like so okay
now what does this all mean well select
we've already said means go and get
select the data okay so that's how we go
and get data this star means I want all
of the columns from the table we're
about to get data from so say for
example each of our records has five
columns right it has an ID it has a
title it has the ingredients and email
and it created out all five columns and
I want all of those five columns of data
when we go to get the data all right
that's what this means the star this
from means where we're getting it from
the data and this pizzas is the name of
our database we called that pizzas
remember not the database sorry the
table the database name is ninja pizza
the table inside that database is pizzas
so that's where we're selecting the data
from so this would go ahead and select
it all I don't want it all I just want
certain columns so the way we do that is
right out the columns that we actually
want I want the title the ingredients
and the ID because we're going to use
that in the future they're the only
three columns that I need right now okay
right so the next step is to actually
make the query and get the results
so we'll say make query and get result
okay so the way we do this is by
creating a variable called results and
set that equal to my sequel I underscore
query because we're making the query
right now we use the connection variable
this is our connection to the database
so this is the information or the
reference it's going to use to go out
and get the data let's spell this
correctly it's my and then the second
parameter or the second argument we need
to pass through is the actual stuff that
we want to issue the command the sequel
so let's toss that in right there like
so so that there my friends is going to
actually make the query to the database
and get us some kind of result right
there all right now that result isn't
just an array of pizzas or anything like
that an array of records we actually
have to get from that result the array
that we want and this is the third step
so we need to fetch the resulting rows
remember each row is basically a record
in a table as an array so that's the
next step okay because they're not
automatically in a reformat here or
anything like that we need to actually
get these pizzas as an array of
different records or different rows so
I'm going to store this in a pizzas
variable and set that equal to my sequel
I and then underscore fetch underscore
all because we want all of them and
we're going to fetch them from the
result that we just got from making this
query right here that's where we're
fetching them from and then we want to
return it as a my sequel i underscore
Assoc
like that and that returns it as an
associative array for us okay so we'll
see that in a minute because I'm going
to print it out in fact what I'll do is
I'll print this out first so
say print underscore R and then we're
going to print out the pizzas okay so
just quickly again what have we done one
second well first of all we've connected
to the database then we've constructed
this query string using select and from
to say where it's from as well then
we've got this variable called result
where we store this query that we're
making via this connection so we know
where we connect into what database and
what issue in this command this sequel
command right here that we constructed
that should get us this data right here
from this table okay now this result
it's not in a format that we can use
what we need to do is fetch the data
from that result in a format that we're
going to use which is what we're doing
here using this function and passing in
that result that we got from the query
and we say we want it back as an
associative array then we're printing
that array to the browser so let me see
if this works
save that and refresh over here and now
we can see we have this array okay so we
can see now a position 0 we have an
array and in there we have a title which
is ninja supreme ingredients the tomato
so these are associative arrays right
these things right here for each pizza
we have an associative array and that's
good because now we can cycle through
those at some point and output them to
the Dom to the browser in the template
down here we're not going to do that
just yet we'll do that in another video
probably the next one to be honest but
for now what I'd like to do is one more
thing so typically after we've done our
query we should first of all free the
results for a memory this is good
practice we don't have to do this but
it's good practice we don't need this
anymore
so we could free it from memory ok so we
can say my sequel i underscore free
underscore results and then in brackets
pass in the result okay so that's the
first step the next step is to close the
connection to the database so we're
going to do that next and I'm just going
to say my sequel i underscore close to
do this and we pass in the connection so
that's the connection that we're closing
right there
so we're freeing the result from memory
so let me just put a comment above that
free results from memory so we don't
need to hang on to that anymore and then
we're closing the connection okay so
that's all there is to it we're writing
the SQL issue in the command
getting the data in a format that we can
use then we're freeing this resort from
memory because we don't need that
anymore
then we're closing the connection and at
the end of it all we have these pizzas
array now we have the data we need and
we can go ahead in the next video and
stats out put that in the HTML template
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