Coldfusion parse date in select statement

If you're asking about database syntax, we need to know what database you're using.

>> The data is in a text field of length 8, and is formatted as YYYYMMDD

It's better to store dates in date/time fields, instead of text. Then you could simply use CF date functions to format it however you want.  

<input type="text" value="#DateFormat(yourQuery.myDate, "MM/DD/YYY")#" ...>

I'm using an odbc driver of type DB/C FS .  I think the data is flat-file based.

This link might explain it better.

http://www.dbcsoftware.com/dbcfstechinfo.html

Unfortunately, I have read-only access to the DB as well, so changing the structure is out of the question

Unfortunately, I can only tell you the syntax for db's like MS SQL, MySQL, Sybase, etc...  I don't know anything about DB/C FS.  

But you could also use CF's string functions.  If the field is always 8 characters, you could use something like:

(Not tested )
<cfset theNewValue = MID(myDate, 5, 2) &"/"& RIGHT(myDate, 2) &"/"& LEFT(myDate, 4)>

Formatting the data after the query is retrieved is not a problem.  I was hope to do it right in the SELECT statement though.

BTW:  Most databases have _some_ version of those 3 string functions. (Though MID is often called substring).  So it's entirely possible yours does too. Meaning you could do the same thing within your query.  Unfortunately, I don't know the syntax for your db type.  

The timing of our posts clashed ...

>> I was hope to do it right in the SELECT statement though.

I know .. But while I'm familiar with a lot of db types, I'm not familiar with yours :( So I don't even know if your db supports those string functions, let alone the function names or syntax.

Is there a list of database functions somewhere? The I could not find much googling ..

All I know is that my driver is supposed to be ODBC 3.0 compatible.  I don't have access to any sort of function list.

I would just go ahead and try some of the standard string functions then.  If they work, great. If not, you're no worse off than you are now.
http://msdn.microsoft.com/en-us/library/ms710249%28VS.85%29.aspx

ie I would try each separately just to see what works and what doesn't

    SELECT  LEFT(YourColumn, 4) AS TestValue FROM YourTable

... then
         SELECT  RIGHT(YourColumn, 2) AS TestValue FROM YourTable

... then
          SELECT  SUBSTRING(YourColumn, 5, 2) AS TestValue FROM YourTable

If they all work, next figure out what your db's concatenation operator is.  It's usually "&" or "+"

          SELECT   YourColumn  & ':::' AS TestConcat FROM YourTable

If by chance all of those work, rearrange them and construct your final query. Note: Substitute the correct concatenation operator if needed

      SELECT  SUBSTRING(YourColumn, 5, 2) &'/'&
                    RIGHT(YourColumn, 2)             &'/'&
                    LEFT(YourColumn, 4)  AS MyDate
      FROM     YourTable

Again, I'm flying blind on this one. But reading further into the ODBC docs suggest functions may be called differently. Try the syntax below as well.

ie  Try
     SELECT {fn SUBSTRING(YourColumn, 5, 2) } FROM YourTable

... as well as

     SELECT  SUBSTRING(YourColumn, 5, 2) FROM YourTable

http://msdn.microsoft.com/en-us/library/ms709434%28VS.85%29.aspx

RIGHT and LEFT both result in    Column not found: RIGHT or  Column not found: LEFT

SUBSTRING results in Parsing error: keyword FROM expected in SUBSTRING operation.

Getting warmer!

I figured it out...looked here:

http://troels.arvin.dk/db/rdbms/#functions-SUBSTRING

and found this syntax :  SUBSTRING(input FROM start-position [FOR length])

What worked for me was:   SUBSTRING(input FROM start-position)

That's a new one!  But won't you need the [FOR length] part to extract only the 2 digits of the month?  

That didn't come out right ;-) What I meant was, if the [FOR length] part works ... then you can obviously use SUBSTRING() instead of left(), right()

BTW: In case & and + don't work for concatenation, try using "||"

Also, just curious but did you have any luck with the { fn ....} style syntax or did it fail?  

|| did work to concatenate.  Thanks so much!  Final question....I have concatenated my value into a date such as 10/21/2010.  I am using a query of queries to pull Sum totals by week from the query that made the concatenated date.  My where clause states "WHERE #week(concatdate)# = #i# , where "i" is the index of a loop from 1 to 53.  The week function is being evaluated immediately though, so the clause only proves true when, for instance, 21=21.  How can I make it eval properly?

>> The week function is being evaluated immediately though

Yeah, that's because it's being executed in CF, _before_ the QoQ. Short story, you can't do what you're trying to do in a QoQ.  They're VERY limited, and don't have any date function support at all.  The best you could do is a very, very ugly hack.  Essentially loop from 1 to 53 and UNION the results together.  

But before you resort to that ... you didn't answer my question about the the special function syntax { fn ...}. Did it work? The reason I ask is because I'm wondering if it provides access to other functions, beyond just the basics.

( BTW: Don't forget to post the final query for others who have the same question in the future :)

unfortunately,  { fn ...} didn't work.... I will post the working query, but do you have an alternative to my approach.  I'd like to query by numbered week, but may dates are text (20100901) and my database archaic.

Darn.  

Thinking about it, I'm not even sure a UNION would work.  I think you would have to loop through the results calculating the totals as you loop.  Not very elegant, but unless your db has some version of the #week()# function, I can't think of any way to avoid it.

How many records AND columns are in the base query?

Query has 5 columns and about 200 records....narrowed down from 4,790,000

I have to head out now. But I'll check back tomorrow.