Mass find and replace of unique identifiers

[sabbirhamid]

Hi

I've inherited a massive dataset that contains many unique identifiers. The unique identifiers are too long for my purposes, and I need to shorten them across the database. Currently unique identifiers are 23 characters long (eg: @I6000000002997995944@), and I need to replace them with identifiers that are 8 characters long (eg @I10001@)

In column A and column C of the database contain references to the 23-character unique identifiers (as well as other content) - these are the columns I need to have content replaced in. I have a list of all 23-character unique identifiers at column G, and the corresponding 8-character unique identifiers in column H.

Basically, I want to know what is the best way to search for values in column G that are contained in column A and column C, and where found, replace them with the corresponding value in column H.

The problem is the database is very big. Column A and C have more than 200,000 values, and the number of unique identifiers is 75,000. Doing a search and replace one by one is not possible.

Sorry if I wasn't clear enough in explaining the issue.

Thanks