在MYSQL中减去2列

Question

您好我想从比尔中减去Coverage并将其从表格TotalBill中加入总计

这将是这样的： 账单 - 承保范围=总计

+------+-----------+-------+  
| Bill | Coverage  | Total |    
+------+-----------+-------+  
| 1300 |       300 |  NULL |    
| 2000 |      1600 |  NULL |     
+------+-----------+-------+

Answer 1

看起来你正在寻找这个

   UPDATE 
     TotalBill
   SET 
     Total = Bill - Coverage