Expression hiccup

[Dan_Oliphant]

I am using this expression in order to link each row with quickbooks. Basically I need each row to have a value of M_T_1, M_T_2, M_T_3, M_T_4, M_T_5. I used this expression to do this as an initial value.
“M_T_”&(COUNT(SELECT(bol_manpower[unique_id], [job_uid] = [_THISROW].[job_uid]))+1)

Simple enough… but the only issue could be if let’s say I delete the row with M_T_2. Then when I add the next row I will have two M_T_5 values. How can I change the expression to understand I am missing the M_T_2 value?

[Dan_Oliphant]

Count(select(bol_manpower[unique_id],
and([job_uid] = [_THISROW].[job_uid],
[_rowNumber]<=[_thisrow].[_rownumber])
))

This is getting closer but still not there. With this, you have to resync every row to get the columns to match

[Suvrutt_Gurjar]

You may wish to take a look at the tip by @Steve

Serial Numbers, If You Must Tips & Tricks 💡

Danger Ahead! In general, sequential numeric identifiers (i.e., serial numbers) are risky in AppSheet: if two users happen to add rows at the same time, both rows could be assigned the same serial number, which could lead to confusion (at the least) or data loss (at the worst). For this reason, serial numbers are strongly discouraged! Basic Serial Numbers One way to implement serial numbers is with a normal (not virtual) column named (e.g.) Serial of type Number and an Initial value expression …