How to join multiple table and sum each field in table?

Question

Database : report
Table 1 : purchase
| date | value_purchase |
| 2019-07-10 | 20 |
| 2019-07-10 | 40 |
| 2019-07-11 | 50 |

Table 2 : sales
| date | value_sales |
| 2019-07-10 | 20 |
| 2019-07-11 | 40 |
| 2019-07-11 | 50 |

I want to showing data :
| date | sum(value_purchase) | sum(value_sales) |
| 2019-07-10 | 60 | 20 |
| 2019-07-11 | 50 | 90 |