问题
I'm newbie to oracle and my question is easy, is possible to convert a CLOB field into NUMBER type to do a comparison.
I´ve tried using CAST and also with TO_NUMBER function but i did not get nothing working.
My attempts:
WHERE TO_NUMBER(clob_field) = 100 -> Error ORA-01722: NOT a valid number
WHERE CAST(clob_field as NUMBER) = 100 -> Error ORA-00932:Inconsistent datatypes
If this is not possible, which would be the best approach to do this?
Thanks for your time and help.
回答1:
Compare it as varchar to get rid of the error message:
WHERE TRIM(clob_field) = '100'
If there is never any whitespace around the 100 you can skip the TRIM:
WHERE clob_field = '100'
回答2:
Cast it first to a VARCHAR2 and then to a NUMBER:
CAST(CAST(clob_field AS VARCHAR2(200)) AS NUMBER(10))
来源：https://stackoverflow.com/questions/22150212/converting-clob-to-number-to-compare-oracle