Re: GETTING FIRST 250 CHARACTERS FROM A LONG DATATYPE

Mark Liggayu wrote:
>
> HI GURUS,
>
> If I have a table that has a field with long data type and I want to get the
> first 250 characters out of it how can I do it. I tried using SUBSTR(long
> data type field, 1, 250) but it complained about "ORA-00932: inconsistent
> datatypes". I then tried TO_CHAR(SUBSTR(long data type field, 1, 250)) but
> still gave me the same result. Tried TO_VARCHAR2 but to no avail.
>
> Thanks,
> Mark
>

You can't apply a function to a LONG (but perhaps the LONG-to-LOB conversions of 8i). If this is possible to you (ie Oracle version supporting it), convert to CLOB or similar. Otherwise, all I can think of is a user-written PL/SQL function (would work with Oracle 7.3 and, of course, above). In PL/SQL, VARCHAR2 can be up to 32K (or around) and you CAN select a LONG into a large enough VARCHAR2. If your LONGs are under 32K, it is easy to write a function LONGSTART which fetches the suitable LONG into a suitably long VARCHAR2, and returns the 250 first characters of this VARCHAR2. Note that I am talking about feasibility, not performance (it may not be THAT bad but I wouldn't do it on millions of rows).

-- 
HTH,

Stephane Faroult
Oriole Corporation
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Author: Stephane Faroult
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