RFC_READ_TABLE is a read data function implemented by SAP to read content from SAP Tables. CData connectors for SAP ERP use this function to read data by default as it comes shipped with every SAP instance. This function is known to have issues on certain scenarios; one of them being incorrect parsing when dealing with negative decimal numbers which have the same number of digits as their declared length.
e.g ON SAP: 358,15698- (decimal 9,5) -> AFTER RFC READ: *8,15698 -
This bad output causes the connector to parse it as NULL or empty (or empty value, depending on the InitialValueMode connection property).
To resolve this issue, you will need to set the ReadTableFunction connection property to Z_CUSTOM_READ_TABLE or Z_CUSTOM_READ_TABLE752 and perform the configuration mentioned in the following documentation:
CData JDBC Driver for SAP ERP - Using a Custom Read Table Function
