| Lists: | pgsql-novice |
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| From: | Bryan Irvine <bryan(dot)irvine(at)kingcountyjournal(dot)com> |
|---|---|
| To: | pgsql-novice(at)postgresql(dot)org |
| Subject: | how many records |
| Date: | 2003-09-10 15:24:06 |
| Message-ID: | 1063207446.32209.1.camel@elvis |
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Is there an easy way to count how many records there are?
--Bryan
| From: | Simon Willison <cs1spw(at)bath(dot)ac(dot)uk> |
|---|---|
| To: | Bryan Irvine <bryan(dot)irvine(at)kingcountyjournal(dot)com> |
| Cc: | pgsql-novice(at)postgresql(dot)org |
| Subject: | Re: how many records |
| Date: | 2003-09-10 17:26:30 |
| Message-ID: | 3F5F5EC6.9060205@bath.ac.uk |
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Bryan Irvine wrote:
> Is there an easy way to count how many records there are?
Yes, using count(*):
select count(*) from tablename;
Hope that helps,
Simon
| From: | "Louise Cofield" <lcofield(at)box-works(dot)com> |
|---|---|
| To: | "'Bryan Irvine'" <bryan(dot)irvine(at)kingcountyjournal(dot)com>, <pgsql-novice(at)postgresql(dot)org> |
| Subject: | Re: how many records |
| Date: | 2003-09-10 17:27:27 |
| Message-ID: | 000c01c377c0$ce742450$7801a8c0@Louise |
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The only way I have found to do this is with COUNT:
select count(*) from <tablename>;
-Louise
-----Original Message-----
From: pgsql-novice-owner(at)postgresql(dot)org
[mailto:pgsql-novice-owner(at)postgresql(dot)org] On Behalf Of Bryan Irvine
Sent: Wednesday, September 10, 2003 9:24 AM
To: pgsql-novice(at)postgresql(dot)org
Subject: [NOVICE] how many records
Is there an easy way to count how many records there are?
--Bryan
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| From: | Oliver Elphick <olly(at)lfix(dot)co(dot)uk> |
|---|---|
| To: | Bryan Irvine <bryan(dot)irvine(at)kingcountyjournal(dot)com> |
| Cc: | pgsql-novice(at)postgresql(dot)org |
| Subject: | Re: how many records |
| Date: | 2003-09-10 17:35:28 |
| Message-ID: | 1063215328.21803.127.camel@linda.lfix.co.uk |
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On Wed, 2003-09-10 at 16:24, Bryan Irvine wrote:
> Is there an easy way to count how many records there are?
SELECT COUNT(*) FROM mytable;
--
Oliver Elphick Oliver(dot)Elphick(at)lfix(dot)co(dot)uk
Isle of Wight, UK http://www.lfix.co.uk/oliver
GPG: 1024D/3E1D0C1C: CA12 09E0 E8D5 8870 5839 932A 614D 4C34 3E1D 0C1C
========================================
"Draw near to God and he will draw near to you.
Cleanse your hands, you sinners; and purify your
hearts, you double minded." James 4:8
| From: | "M(dot) Bastin" <marcbastin(at)mindspring(dot)com> |
|---|---|
| To: | Bryan Irvine <bryan(dot)irvine(at)kingcountyjournal(dot)com> |
| Cc: | pgsql-novice(at)postgresql(dot)org |
| Subject: | Re: how many records |
| Date: | 2003-09-10 17:38:34 |
| Message-ID: | a0600200abb8511fc9f4b@[192.168.0.14] |
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SELECT COUNT(*) FROM mytable;
Marc
>Is there an easy way to count how many records there are?
>
>--Bryan
>
>
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| From: | Stuart Woodward <woodward(at)garage(dot)co(dot)jp> |
|---|---|
| To: | pgsql-novice(at)postgresql(dot)org |
| Subject: | Re: how many records |
| Date: | 2003-09-11 01:20:23 |
| Message-ID: | 20030911101954.F765.WOODWARD@garage.co.jp |
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> Bryan Irvine wrote:
> Is there an easy way to count how many records there are?
On Wed, 10 Sep 2003 18:26:30 +0100
Simon Willison <cs1spw(at)bath(dot)ac(dot)uk> wrote:
> Yes, using count(*):
> select count(*) from tablename;
Is there any performance difference in explicitly naming a column to
count?
i.e select count(id) from tablename;
(I know that a lot of beginners always "select *" even when they don't
need all the information which (I think) is slower than selecting just
what need.)
| From: | Bruno Wolff III <bruno(at)wolff(dot)to> |
|---|---|
| To: | Stuart Woodward <woodward(at)garage(dot)co(dot)jp> |
| Cc: | pgsql-novice(at)postgresql(dot)org |
| Subject: | Re: how many records |
| Date: | 2003-09-11 01:50:27 |
| Message-ID: | 20030911015027.GA8580@wolff.to |
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On Thu, Sep 11, 2003 at 10:20:23 +0900,
Stuart Woodward <woodward(at)garage(dot)co(dot)jp> wrote:
> > Bryan Irvine wrote:
> > Is there an easy way to count how many records there are?
>
> On Wed, 10 Sep 2003 18:26:30 +0100
> Simon Willison <cs1spw(at)bath(dot)ac(dot)uk> wrote:
>
> > Yes, using count(*):
> > select count(*) from tablename;
>
> Is there any performance difference in explicitly naming a column to
> count?
>
> i.e select count(id) from tablename;
Note that select count(id) and select count(*) can return different numbers.
Select count(*) is equivalent to select count(1) and I believe that
transformation (or something equivalent) is made by postgres.