尝试从 table 获取总数时 Rust diesel 面临错误

Question

我正在使用 rust diesel 实现一个数据库。我想使用具有 filter 条件的查询来获取 table 中存在的总计数或总列数。下面是我的 table 结构和查询代码。我没有在我的 table 结构中使用任何 BIGINT, 大的小数。

the trait bound i32: FromSql<BigInt, Pg> is not satisfied the following implementations were found: <i32 as FromSql<Integer, DB>> required because of the requirements on the impl of diesel::Queryable<BigInt, Pg> for i32 required because of the requirements on the impl of LoadQuery<PooledConnection<ConnectionManager<PgConnection>>, i32> for

#Emplyee table

| employee-id  | employee_name | empolyee_email|       
| -----------  | --------------|-------------  |
| 1            | ABC           |abc@mail.com   |
| 2            | xyz           |xyz@mail.com   |


# Account table

| account  | employee-id    | account-balnce | created_at|
| -------- | ----------     |--------------- |-----------|
| 1        | 1              |   2000         | 22/10/2021|
| 2        | 2              |   5000         | 01/09/2021|

fn get_total_accounts(&self, employee_id: &str) -> anyhow::Result<Option<i32>> {
        let res: i32 = employee::table
            .inner_join(account::table)
            .filter(employee::dsl::employee_id.eq(employee_id))
            .count()
            .get_result(&self.pool.get()?)?;  //get_result through error
               
 }

Answer 1

使用 I64 解决了我的问题。

fn get_total_accounts(&self, employee_id: &str) -> anyhow::Result<Option<i32>> {
        let res: i64 = employee::table
            .inner_join(account::table)
            .filter(employee::dsl::employee_id.eq(employee_id))
            .count()
            .get_result(&self.pool.get()?)?;  //get_result through error
               
 }

尝试从 table 获取总数时 Rust diesel 面临错误

Rust diesel facing error when trying to get total count from table

rust

rust-diesel