From several table VS inner join
up vote
0
down vote
favorite
I can't get the point.
What is the difference between
select e.empid
from employee_table e
inner join customer_table c
on deref(c.infos).personid = deref(e.infos).personid
order by e.empid;
and
select e.empid
from employee_table e, customer_table c
where deref(c.infos).personid = deref(e.infos).personid
order by e.empid;
The results are the same.
Is one faster to perform than the other ?
When to use an inner join when we can simply select from multiple table ?
sql inner-join
asked Apr 13 '17 at 18:32
Guilhem Fry
607
add a comment |
up vote
0
down vote
favorite
I can't get the point.
What is the difference between
select e.empid
from employee_table e
inner join customer_table c
on deref(c.infos).personid = deref(e.infos).personid
order by e.empid;
and
select e.empid
from employee_table e, customer_table c
where deref(c.infos).personid = deref(e.infos).personid
order by e.empid;
The results are the same.
Is one faster to perform than the other ?
When to use an inner join when we can simply select from multiple table ?
sql inner-join
asked Apr 13 '17 at 18:32
Guilhem Fry
607
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
I can't get the point.
What is the difference between
select e.empid
from employee_table e
inner join customer_table c
on deref(c.infos).personid = deref(e.infos).personid
order by e.empid;
and
select e.empid
from employee_table e, customer_table c
where deref(c.infos).personid = deref(e.infos).personid
order by e.empid;
The results are the same.
Is one faster to perform than the other ?
When to use an inner join when we can simply select from multiple table ?
sql inner-join
asked Apr 13 '17 at 18:32
Guilhem Fry
607
I can't get the point.
What is the difference between
select e.empid
from employee_table e
inner join customer_table c
on deref(c.infos).personid = deref(e.infos).personid
order by e.empid;
and
select e.empid
from employee_table e, customer_table c
where deref(c.infos).personid = deref(e.infos).personid
order by e.empid;
The results are the same.
Is one faster to perform than the other ?
When to use an inner join when we can simply select from multiple table ?
sql inner-join
sql inner-join
asked Apr 13 '17 at 18:32
Guilhem Fry
607
asked Apr 13 '17 at 18:32
Guilhem Fry
607
edited Apr 13 '17 at 18:46
asked Apr 13 '17 at 18:32
Guilhem Fry
607
asked Apr 13 '17 at 18:32
Guilhem Fry
607
asked Apr 13 '17 at 18:32
Guilhem Fry
607
607
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
up vote
1
down vote
accepted
Because these two queries are equivalent. But the first one is using ANSI-92 style joins and the second is using ANSI-89 style joins. The newer join syntax is less prone to error and it has been around for 25 years now.
You should always use the ANSI-92 style joins.
- Bad habits to kick : using old-style JOINs
edited Nov 10 at 22:04
Aaron Bertrand
206k27358401
answered Apr 13 '17 at 18:44
Sean Lange
24.2k21735
I edited the post for e.supervisor. Thank you for the advice. Does it run exacltly the same in the sql engine ?
– Guilhem Fry
Apr 13 '17 at 18:47
Well I don't know which sql engine but these are ANSI standards and nearly every DBMS follows these pretty close. Certainly on joins all of the major ones will be identical.
– Sean Lange
Apr 13 '17 at 18:48
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
1
down vote
accepted
Because these two queries are equivalent. But the first one is using ANSI-92 style joins and the second is using ANSI-89 style joins. The newer join syntax is less prone to error and it has been around for 25 years now.
You should always use the ANSI-92 style joins.
- Bad habits to kick : using old-style JOINs
edited Nov 10 at 22:04
Aaron Bertrand
206k27358401
answered Apr 13 '17 at 18:44
Sean Lange
24.2k21735
I edited the post for e.supervisor. Thank you for the advice. Does it run exacltly the same in the sql engine ?
– Guilhem Fry
Apr 13 '17 at 18:47
Well I don't know which sql engine but these are ANSI standards and nearly every DBMS follows these pretty close. Certainly on joins all of the major ones will be identical.
– Sean Lange
Apr 13 '17 at 18:48
add a comment |
up vote
1
down vote
accepted
Because these two queries are equivalent. But the first one is using ANSI-92 style joins and the second is using ANSI-89 style joins. The newer join syntax is less prone to error and it has been around for 25 years now.
You should always use the ANSI-92 style joins.
- Bad habits to kick : using old-style JOINs
edited Nov 10 at 22:04
Aaron Bertrand
206k27358401
answered Apr 13 '17 at 18:44
Sean Lange
24.2k21735
I edited the post for e.supervisor. Thank you for the advice. Does it run exacltly the same in the sql engine ?
– Guilhem Fry
Apr 13 '17 at 18:47
Well I don't know which sql engine but these are ANSI standards and nearly every DBMS follows these pretty close. Certainly on joins all of the major ones will be identical.
– Sean Lange
Apr 13 '17 at 18:48
add a comment |
up vote
1
down vote
accepted
up vote
1
down vote
accepted
Because these two queries are equivalent. But the first one is using ANSI-92 style joins and the second is using ANSI-89 style joins. The newer join syntax is less prone to error and it has been around for 25 years now.
You should always use the ANSI-92 style joins.
- Bad habits to kick : using old-style JOINs
edited Nov 10 at 22:04
Aaron Bertrand
206k27358401
answered Apr 13 '17 at 18:44
Sean Lange
24.2k21735
Because these two queries are equivalent. But the first one is using ANSI-92 style joins and the second is using ANSI-89 style joins. The newer join syntax is less prone to error and it has been around for 25 years now.
You should always use the ANSI-92 style joins.
- Bad habits to kick : using old-style JOINs
edited Nov 10 at 22:04
Aaron Bertrand
206k27358401
answered Apr 13 '17 at 18:44
Sean Lange
24.2k21735
edited Nov 10 at 22:04
Aaron Bertrand
206k27358401
edited Nov 10 at 22:04
Aaron Bertrand
206k27358401
edited Nov 10 at 22:04
Aaron Bertrand
206k27358401
206k27358401
answered Apr 13 '17 at 18:44
Sean Lange
24.2k21735
answered Apr 13 '17 at 18:44
Sean Lange
24.2k21735
answered Apr 13 '17 at 18:44
Sean Lange
24.2k21735
24.2k21735
I edited the post for e.supervisor. Thank you for the advice. Does it run exacltly the same in the sql engine ?
– Guilhem Fry
Apr 13 '17 at 18:47
Well I don't know which sql engine but these are ANSI standards and nearly every DBMS follows these pretty close. Certainly on joins all of the major ones will be identical.
– Sean Lange
Apr 13 '17 at 18:48
add a comment |
I edited the post for e.supervisor. Thank you for the advice. Does it run exacltly the same in the sql engine ?
– Guilhem Fry
Apr 13 '17 at 18:47
Well I don't know which sql engine but these are ANSI standards and nearly every DBMS follows these pretty close. Certainly on joins all of the major ones will be identical.
– Sean Lange
Apr 13 '17 at 18:48
I edited the post for e.supervisor. Thank you for the advice. Does it run exacltly the same in the sql engine ?
– Guilhem Fry
Apr 13 '17 at 18:47
I edited the post for e.supervisor. Thank you for the advice. Does it run exacltly the same in the sql engine ?
– Guilhem Fry
Apr 13 '17 at 18:47
Well I don't know which sql engine but these are ANSI standards and nearly every DBMS follows these pretty close. Certainly on joins all of the major ones will be identical.
– Sean Lange
Apr 13 '17 at 18:48
Well I don't know which sql engine but these are ANSI standards and nearly every DBMS follows these pretty close. Certainly on joins all of the major ones will be identical.
– Sean Lange
Apr 13 '17 at 18:48
add a comment |
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