I want to achieve outstanding billing amount.
| Invoice No. | Invoice Date | Client Name | Sectors | State | Billing YTD | |
| 1 | 28-09-2014 | Kaqvi Nprvynn (Xwpxmp) Nzokaly | Insurance | Chennai | -13980405 |
| 2 | 27-10-2014 | Dqb Vwrfgevx amt Hbfckdkb Zrjxpbg Gniedyvjyxt Adq. | Health | Maharashtra | 5756 |
above fields are of main table, here I need to create Credit table and Invoice table . After which outstanding Billing amount
