Situation:
In version13, Custom field Allowance created in Salary Structure Assignment as varchar. User changed mind to use it as value after initial creation. The user removed the Data field and added a Currency field.
On migration from v13 to v14 the database threw error that pymysql.err.DataError: (1265, "Data truncated for column 'allowance' at row 68")
Solution:
Had to update tabSalary Structure Assignment set allowance = 0 where allowance is null;
update tabSalary Structure Assignment set allowance = cast(allowance as decimal(21,9));
delete from tabModule Def where name = ‘HR’;
delete from tabModule Def where name = ‘Payroll’;
And had to install the hrms app on v14 site since it was coming from v13
Hope it helps others.