I know what you are talking about for bill numbering increment by one because I did that but with far more evaluation than four digits (i.e. 1010). To answer your original question.
UPDATE tblTableName
SET Field1 = Value1, Field2 = Value2, Field3 = Value3, etc
WHERE Field1 = CurrentValue1, Field2 = CurrentValue2, Field3 = CurrentValue3;
Add or subtract whatever fields and values you do not want to change.
For example just add your second 15th Oct 2017 so it has everything as all other bills have, including the 1019.
Then do the update starting with your most recent bill number (the second 15th Oct 2017) and set it to 1020. Then work in reverse with 1018 to 1019, 1017 to 1018, 1016 to 1017, and so forth since it opens up a place holder for the bill number itself. Then at the very end of the update add another entry for the second 15th Oct 2017 and set it to 1011.
Just be careful though because this can mess your database up if not done right. Note I have not done this in a while so you may need to do each one individually using the same order described above and shown below.
Example:
Code:
UPDATE tblSale
SET [BillNumber1] = 1020, [BillNumber2] = 1019, [BillNumber3] = 1018, etc
WHERE [BillNumber1] = 1019, [BillNumber2] = 1018, [BillNumber3] = 1017, etc;
The "SET" is what you want it to be.
The "WHERE" is what it currently is.
The "WHERE" runs first for the statement so it knows what it is looking at then it "SET" the new value based on order 1, 2, 3, etc for both "WHERE" and "SET".
The BillNumber1, 2, 3 is the same field that I am just showing as being for separate billing numbers, so they should all be like [BillNumber] = 1019, [BillNumber] = 1018, etc if the information you gave is correct.