This optional parameter allows you to customise the exact form of the insert query used to insert accounting data. All date formatting characters are permitted. For more information, see Section 3.4. Date formatting. %0 is replaced with the value of the AccountingTable parameter. %1 is replaced with the comma separated list of column names to be inserted (derived from Acct- ColumnDef), and %2 is replaced by the data values to be inserted for each column in the same order as %1. The columns and values will be in alphabetical order by column name. The default is ‘insert into %0 (%1) values (%2)’.

You can use this to use special features in your SQL server, such as this for MySQL:

# maybe update if this is a duplicate
AcctInsertQuery update or insert into %0 (%1) values (%2)