Database

20-Aug-09 3:50

Hi guys,

I'm struggling with something conceptually that maybe somebody would be able to help me with. I'm writing an application to match vehicles in one database to vehicle in another database. As you can imagine there are difference all over the place so there will be a lot of manual matching to be done but I'm doing my best to cut down on the amount of manual work where possible. The LIKE predicate has definitely been my friend here, but how can I make it work the other way around, i.e. instead of C_Model LIKE '%Fiesta%' I could do with 'Fiesta' LIKE %C_Model%. If you know what I mean?

For instance I can match this:

DB1          DB2
'Fiesta'  -> 'Fiesta 1'
          -> 'Fiesta 2'
          -> 'Fiesta 3'

...but I don't know how to go this way:

DB1           DB2
'306 -97' -> '306'
'306 97-' -> '306'

Cheers,

Chris Chambers.

Mycroft Holmes20-Aug-09 4:17

20-Aug-09 4:17

You may now get ready to kick yourself....

You have no problem getting DB2 like 'Fietsa%'
what is wrong with getting Db1 like '306%'

Never underestimate the power of human stupidity
RAH

TheIdleProgrammer20-Aug-09 4:28

20-Aug-09 4:28

Yeah, maybe I should have explained myself better.

Take this statement from the second databases DataSet class:

return (ModelsRow[])this.Models.Select("C_Make = '" + make + "' AND C_Model LIKE '%" + model + "%'");

Is there an expression I can use to try to further enhance this expression to help me retrieve the records where C_Model is like the model passed in? If '306 -97' is passed in and the models table contains '306' rows how can I get to those rows? Like I say, it's fine if I pass in 'Fiesta' and the models table contains 'Fiesta 1', 'Fiesta 2', 'Fiesta 3' etc.

The more I think about this the more I'm beginning to think it's not possible. I just don't see how I can select rows where a certain field matches a substring of a literal string.

Mycroft Holmes20-Aug-09 13:15

20-Aug-09 13:15

return (ModelsRow[])this.Models.Select("C_Make = '" + make + "' AND C_Model LIKE '%" + model + "%' or C_Model like '306%'");

This answer is too simple I must be missing something in your question.

I use stored procs for 99.9% of my database work and therefore can design the SQL to do exactly what I want in QA/EM. I suggest you do this to get the result you want and then move it to a string if that is where you want to have you SQL. Also look into parameterised queries, you current model is subject to sql injection.

Never underestimate the power of human stupidity
RAH

TheIdleProgrammer20-Aug-09 22:10

20-Aug-09 22:10

Hi Mycroft,

Mycroft Holmes wrote:
return (ModelsRow[])this.Models.Select("C_Make = '" + make + "' AND C_Model LIKE '%" + model + "%' or C_Model like '306%'");

This won't work because the '306' is what's actually in C_Model; at the point this statement is executed I don't actually know what that is. I just used that '306' string as a typical example.

To be honest, the more I've thought about this the more I've decided it's a stupid thing to do in the context of my application anyway so I've abandoned the idea for now. I'm sorry if I've wasted your time. Many thanks for your help anyway.

Thanks again,

Chris Chambers.

Mycroft Holmes21-Aug-09 0:33

21-Aug-09 0:33

Not a problem

Never underestimate the power of human stupidity
RAH

David Skelly20-Aug-09 22:53

David Skelly

20-Aug-09 22:53

I'm not sure if I understand your question. I think this will do what you want:

select * from Models
where C_Model like '%306 -97%'
or '306 -97' like C_Model + '%'

It won't be the fastest query in the world, but it should do what you want. It will pick out models that have 306 -97 anywhere in the model number, (e.g. '4306 -97') and it will also get all the rows with model numbers '306'. If there are any rows with model number '3' or '30' it will get those too, but that's what you seem to be asking for.

TheIdleProgrammer20-Aug-09 23:07

20-Aug-09 23:07

Hi David, thanks for your input.

I might try that to see if it works in my application, however as you rightly said it's likely to pick up quite a few entries that I don't want so as I said to Mycroft I think I've decided not to go ahead with it. I'll let you know if that works though.

Regards,

Chris Chambers.

Luc Pattyn20-Aug-09 4:58

Luc Pattyn

20-Aug-09 4:58

I think Mycroft is right.

And if all else fails, you could still use substrings and go for an exact match of the first N characters.

Smile | :)

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TheIdleProgrammer20-Aug-09 22:11

set row number in select query

20-Aug-09 22:11

Thanks for your input Luc, much appreciated.

Regards,

Chris Chambers.

Sql Problem

AhmedGebaly19-Aug-09 23:37

AhmedGebaly

19-Aug-09 23:37

Id Credit Debit CurrentCredit Current Debit
51 21500 0 21500 0
52 0 21500 0 0
89 0 2150 0 2150
93 0 2140 0 4290
128 2140.5 0 0 2149.5
129 2151.5 0 2 0
171 0 1628 0 1626
190 1628 0 2 0

i have column of credit and debit and want to get columns of current credit and current debit
example:
51. credit=21500 and debit=0
i have credit more than debit so this increase credit and decrease debit
then
current credit = 0+21500

52. credit=0 and debit=21500
i have debit more than credit so this decrease credit and increase debit
then current credit =0 and current debit =0

89 credit=0 and debit =2150
i have debit more than credit so this decrease credit and increase debit
then current credit =0 and current debit=0+2150=2150

93 credit=0 and debit =2140
i have debit more than credit so this decrease credit and increase debit
then current credit =0 and current debit=2140+2150= 4290
and so on...

Re: Sql Problem

David Skelly20-Aug-09 2:26

David Skelly

20-Aug-09 2:26

That's very interesting. Is there a question in there?

Re: Sql Problem

Kschuler20-Aug-09 3:17

Kschuler

20-Aug-09 3:17

Are you just looking for this?

SELECT SUM(CurrentCredit) - SUM(CurrentDebit) AS FinalBalance FROM myTable

Re: Sql Problem

Jerry Hammond20-Aug-09 3:41

Jerry Hammond

20-Aug-09 3:41

As interesting as your data is, what is your query?

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nainakarri19-Aug-09 20:34

nainakarri

19-Aug-09 20:34

Hi
I have a table with duplicate rows and distinct id. I have written a select query using distinct and selecting only required fields to avoid duplicates.

Select dictinct(occassion), startdate from table1

Now what i want is to give unique row number to each distict row

For this i tried as below but could not succeed
Declare @num int
set @num =0
select (set @num = @num+1) as num,
dictinct(occassion), startdate from table1

After search in google , i got row_number(). But this i am unable to use as i am using distinct. Can u pls let me know how i can achieve this.

Thanks in advance
Naina

Naina

Re: set row number in select query

_Damian S_19-Aug-09 20:41

_Damian S_

19-Aug-09 20:41

What are you going to do with the unique row number? How will it assist you? Where are you using it?

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Re: set row number in select query

nainakarri19-Aug-09 20:44

nainakarri

19-Aug-09 20:44

Hi

Thanks for the reply.
It is very useful for me. As i will use it in my web page (front end) where other functionality related to this unique number is related to.
Please help me to get this.
Regards
Naina

Naina

Re: set row number in select query

Coding C#20-Aug-09 3:36

Coding C#

20-Aug-09 3:36

Cant you just use ID in the record from table itself?

Coding C#

ExciteTemplate

how to connect to magic database

elimpiado19-Aug-09 19:53

elimpiado

19-Aug-09 19:53

hi all,

would like to receive help on how to connect to a magic software database using vb.net.

thank you very much.

Re: how to connect to magic database

Mycroft Holmes19-Aug-09 20:22