SQL for extract portion of a string
I have a zipcode stored in a text field (string) and would like to select only the last 3 digits of the value in my select statement. is this possible? Is there a standard way of doing this so that the SQL is interchangeable accross databases? I will be using it in production on Oracle, but i test on Interbase (yes, yes, i know, two totally diff DBs, but thats what i am doing)
thanks for 开发者_如何学Cany help you can offer
Assuming the zipcodes all have the same length, you can use substr
.
If they don't have the same length, you have to do similar things with the strlen
function.
Interbase does not have a built-in substring function, but it does have a UDF
(user defined function) called SUBSTR
in lib_udf.dll
that works like this:
select substr(clients.lastname, 1, 10)
from clients
You declare the UDF like this:
DECLARE EXTERNAL FUNCTION SUBSTR
CSTRING(80),
SMALLINT,
SMALLINT
RETURNS CSTRING(80) FREE_IT
ENTRY_POINT 'IB_UDF_substr' MODULE_NAME 'ib_udf';
Oracle does have a built-in substr function that you use like this:
select substr(clients.lastname, 1, 10)
from clients
--jeroen
This depends on how your storing the zip code. If you are using 5 digits only then this should work for Oracle and may work for Interbase.
select * from table where substr(zip,3,3) = '014'
IF you store Zip + 4 and you want the last 3 digits and some are 5 digits and some are 9 digits you would have to do the following.
select * from table where substr(zip,length(zip) -2,3) = '014'
and one option that may work better in both databases is
select * from table where zip like '%014'
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