问题
Scenario: I am calling a function that returns a field that the user enters in. The field usually returns a number like '120000' which I then use to_char to convert into '120,000'.
Problem: Some users enter in values such as '120,000' which gives me an error when trying to use to_char. Also the function will return a space ' ' if no value is found. I tried something with to_number earlier and it has a problem with the ' ' I believe.
Question: What would be the best way to handle this problem? Case statement checking for the ','? Using to_number then to_char?
Note: I can hack a solution together I'm just wondering what the best way to handle this is.
回答1:
Rather than using REPLACE you should use the more powerful REGEXP_REPLACE function.
http://www.orafaq.com/wiki/REGEXP_REPLACE
You can then remove any non-numeric character from the string before then formatting it however you like.
In your case it would be something like:
REGEXP_REPLACE(<your field>, '[^0-9]+', '');
This replaces all non-numeric characters with null effectively removing them from the string.
See this answer too: Oracle: Replacing non-numeric chars in a string
来源：https://stackoverflow.com/questions/9069278/oracle-to-char-function-how-to-handle-if-its-already-a-string