# a question from KDB beginner
**URL:** https://forum.kx.com/t/a-question-from-kdb-beginner/7268
**Category:** Community Support
**Tags:** kdb-and-q
**Created:** [September 2, 2011, 10:43am UTC](https://forum.kx.com/t/a-question-from-kdb-beginner/7268 "2011-09-02T10:43:00Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@Wei\_Li](https://forum.kx.com/u/Wei_Li)
#### Post date: [September 2, 2011, 10:43am UTC](https://forum.kx.com/t/a-question-from-kdb-beginner/7268/1 "2011-09-02T10:43:00Z")
Hi everyone,Recently I started to learn KDB, and I saw some working codes asfollowinghCx:hopen `:eqkdb8p:12000hCx({select cnt:count i from corrTab};::)I tried to run them in q session and they work very well. The firstline is just to connect to KDB host. But the second line is veryconfusing. Especially corrTab is neither a q keyword nor a variable/table defined. Why it works and print outcnt-------9415683Can anyone help?Thanks
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### Author:  [@trieder](https://forum.kx.com/u/trieder)
#### Post date: [September 2, 2011, 11:15am UTC](https://forum.kx.com/t/a-question-from-kdb-beginner/7268/2 "2011-09-02T11:15:00Z")
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For you to understand this you need to read the manuals or q for mortals. In=
particular the sections on ipc, data types (in this case lists) and functio=
ns.
In a nutshell it’s sending a function to the remote host which is simply exe=
cuting the query.
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### Author:  [@charlie1](https://forum.kx.com/u/charlie1)
#### Post date: [September 2, 2011, 11:26am UTC](https://forum.kx.com/t/a-question-from-kdb-beginner/7268/3 "2011-09-02T11:26:00Z")
hCx ({select cnt:count i from corrTab};::)
is sending the list ({select cnt:count i from corrTab};::) to the socket referred to by hCx.
({select cnt:count i from corrTab};::)
is a 2 element list, a lambda (anonymous function) and identity (::).
It’s possible to evaluate a single level parse tree as
q)value ({x+y};2;3)
and that’s what is happening here, except ({select cnt:count i from corrTab};::) is being recompiled and evaluated remotely.
Presumably corrTab is defined on the remote system.
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### Author:  [@rathore\_ajay1](https://forum.kx.com/u/rathore_ajay1)
#### Post date: [September 2, 2011, 1:16pm UTC](https://forum.kx.com/t/a-question-from-kdb-beginner/7268/4 "2011-09-02T13:16:00Z")
In this case, you are connecting to a different kdb process andsending an anonymous function {select cnt:count i from corrTab} andidentity to be executed in that process. So here corrTab is a tabledefined the q process running on eqkdb8p at port 12000. This isequivalent to executing this query on that remote process “selectcnt:count i from corrTab”. Hope this answers your question.Another way to do the same thing would behCx:hopen `:eqkdb8p:12000hCx "select cnt:count i from corrTab"On Sep 2, 5:43?am, Wei Li wrote:> Hi everyone,> Recently I started to learn KDB, and I saw some working codes as> following>> hCx:hopen `:eqkdb8p:12000\> hCx({select cnt:count i from corrTab};::)\>\> I tried to run them in q session and they work very well. The first\> line is just to connect to KDB host. But the second line is very\> confusing. Especially corrTab is neither a q keyword nor a variable/\> table defined. Why it works and print out\>\> cnt\> -------\> 9415683\>\> Can anyone help?\> Thanks\
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### Author:  [@Aaron\_Davies](https://forum.kx.com/u/Aaron_Davies)
#### Post date: [September 2, 2011, 6:44pm UTC](https://forum.kx.com/t/a-question-from-kdb-beginner/7268/5 "2011-09-02T18:44:00Z")
\> Another way to do the same thing would be
\>
\>
\> hCx:hopen `:eqkdb8p:12000
\> hCx “select cnt:count i from corrTab”
slightly more precisely,
hCx “{select cnt:count i from corrTab}”
sending (::) as an arg is the equivalent of invoking with
–
Aaron Davies
aaron.davies@gmail.com
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### Author:  [@Wei\_Li](https://forum.kx.com/u/Wei_Li)
#### Post date: [September 7, 2011, 1:59pm UTC](https://forum.kx.com/t/a-question-from-kdb-beginner/7268/6 "2011-09-07T13:59:00Z")
Thanks all for help.Now I understand it.On Sep 3, 1:44?am, Aaron Davies \ wrote:\> \> Another way to do the same thing would be\>\> \> hCx:hopen `:eqkdb8p:12000\> \> hCx “select cnt:count i from corrTab”\>\> slightly more precisely,\>\> hCx “{select cnt:count i from corrTab}”\>\> sending (::) as an arg is the equivalent of invoking with \>\> –\> Aaron Davies\> [aaron.dav...@gmail.com](mailto:aaron.dav...@gmail.com)\