The Salesforce API provides exponential value when there are more than 8 digits in the currency field. As shown in the below screenshot, Annual Revenue is a currency field in Salesforce Account Object and value within that field is “139,000,000” which is more than 8 digits.
So, when the same is been previewed via DBSync Advanced Query Builder. The value would show as “1.39E8”, which is nothing but an exponential value and it is not issued with DBSync or the UI but it is how salesforce API gives the response on external applications. This value may or may not be accepted by the target system.
The best practice is to have this converted to an exact number which is the same as in Salesforce UI and send it to the target system. This can be done using the DBsync standard function FORMAT. This is the mapping for the target field - FORMAT(VALUE("AnnualRevenue"), "0.0")
Post the sync target system will have the value as shown below in the screenshot.