sql - REGEXP to insert special characters, not remove -

how put double quotes around 2 fields missing it? able use instr/substr/replace in 1 statement accomplish it?

string := '"es26653","abcbeverages","861526999728",606.32,"2017-01-26","2017-01-27","","",77910467,"dorothy","","rapp","14219 pierce street, apt1","","omaha","ne","68144"';  expected string := '"es26653","abcbeverages","861526999728","**606.32**","2017-01-26","2017-01-27","","","**77910467**","dorothy","","rapp","14219 pierce street, apt1","","omaha","ne","68144"'; 

please suggest! thank you.

this answer not work in case, because fields contain commas. leaving in case helps else.

one rather brute force method internal fields is:

replace(replace(string, ',', '","'), '""', '"') 

this adds double quotes on either side of comma , removes double double quotes. don't need worry "". becomes """" , "".

this can adapted first , last fields well, complicates expression.