"Ed Reed" <EReed@stripped> wrote on 03/24/2005 04:02:28 PM:
> Sorry everyone for not being more clear. The field IS in a multiline
> varchar field. The example data was all from one record in the table.
>
> Unfortunately, this is a database that has been around for many years
> and backward compatibility with other apps limits redesigning the table.
> It is a Comments field and this is the first time anyone has ever tried
> to mine any data from it. My app is a generic report writer that simply
> takes and query string and returns the results. No processing of the
> data can be done in the app. I need the result to come directly from
> MySQL.
>
> Thanks again.
>
> - Ed
>
> >>> Keith Ivey <keith@stripped> 3/24/05 12:04 PM >>>
> Dan Nelson wrote:
>
> > How about:
> >
> > SELECT LEFT(description, 8) FROM mytable WHERE description LIKE
> "%tested this%" LIMIT 1
>
> Hmm, I assumed he was talking about a multi-line VARCHAR, but
> now that I look again Dan's interpretation is probably the right
> one. My previous message doesn't apply (except for the bit
> about breaking it into columns if you're doing it regularly).
>
> --
> Keith Ivey < keith@stripped >
> Smokefree DC
> http://www.smokefreedc.org
> Washington, DC
>
Then I think you are stuck. What you are trying to find is a minimum
value from a certain kind of row within a block of undelimited text.
That's like hiding a whole table within a field and trying to write a
query to find a field within the table within the field. Unless your text
happens to be extremely well formatted, you have no chance of doing an
extract in pure SQL and I would say this is definitely not possible using
a single SQL statement.
It may be possible in a single statement if you create a custom UDF that
parses through that "comments" field. Suppose you wrote the UDF to use
this API
FIND_IN_COMMENTS(<part you want>,<field to search>)
Then you could program the UDF to find various <part>s like "first test
date", "last test date", "first review date", "First review person", etc.
in any field that looks like your comments block. However, I believe that
this kind of text manipulation and searching is more complex than can be
easily achieved through just SQL and defintely too complex for a single
statement.
Shawn Green
Database Administrator
Unimin Corporation - Spruce Pine
