get_results using sql_query not returning array of inserted rows , Postgres 15, Rust 1.70.0 , Diesel 2.0

Able to add rows into the table but sql_query(query).get_results does not return array of rows. i.e. I am getting a null array though data gets inserted.

When get_results is used with Select statement an array of values is returned.

Not sure what I am doing wrong. Please advise.

The struct Asset has #[derive(QueryableByName)].
Thank you.

#[test]
fn test_get_result(){
     use crate::service_tests::prelude::connection_without_transaction;
     use diesel::sql_query;
     use diesel::RunQueryDsl;

     use crate::models::asset::Asset;

     let mut connection = connection_without_transaction();

     let query = "Select * from assets";
     let result1 = diesel::sql_query(query)
                            .get_results::<Asset>(&mut connection)
                            .unwrap();
    dbg!(result1.len());

    let query = "insert into assets (
        parent_assetcode,category_code,label_code,
        erp_code,name,description,is_depreciable,
        physical_id,machine_tag_no,in_store,
        quantity,is_multiple_entries,group_qty,
        acquired_value,acquired_date,date_put_to_use,
        physical_verification,asset_type,asset_user,
        cost_center_code,department_code,branch_code,
        location_code,physical_location_code,requires_maintenance,
        created_user_id,remarks
        )
        values
        (
            'BL00000SP','BLD','L-BLD-2','BL00000SP',
            'name of asset','descr',false,'aaaa',
            'mactag',true,1200,false,10,13250.0,
            '2023-05-01','2023-05-02',true,'Owned',
            1,'162','NA','MA003','276 VMART PATNA KURJI',
            'NA',false,1,'remarksss'
        )";
     let result2 = diesel::sql_query(query)
                        .get_results::<Asset>(&mut connection)
                        .unwrap();
     dbg!(result2.len());

}

The output is below:

running 1 test
[src/service_tests/csv_import_test.rs:53] result1.len() = 44
[src/service_tests/csv_import_test.rs:78] result2.len() = 0
test service_tests::csv_import_test::test_get_result ... ok

migrations - up.sql ->

/// after installing diesel , using diesel migration generate create table plans to query,
/// then run diesel setup and diesel migration run to update schema.rs
create table plans(
    id serial not null,
    code varchar(20) not null,
    constraint pk_test_id primary key(id)
);

models\plan.rs ->

/// create a file - plan.rs under models directory plan.rs
// add the following code - creates a struct to query hold values from table plans

use diesel::prelude::*;
use serde::{Deserialize, Serialize};

use crate::schema::plans;

#[derive(Debug, Clone, Identifiable, Insertable, AsChangeset, Queryable,QueryableByName,Deserialize,Serialize)]
#[diesel(table_name = plans)]
#[diesel(primary_key(code))]
pub struct Plan {
    pub id: i32,
    pub code: String
}

services_test_plan.rs

/// create a test file - services_test_plan.rs with the following code
// run the test using from terminal >> cargo test test_get_result_plans
#[test]
fn test_get_result_plans(){
    use crate::service_tests::prelude::connection_without_transaction;
    use diesel::sql_query;
    use diesel::RunQueryDsl;

    use crate::models::test::Plan;
    use crate::schema::plans::code;
    use crate::schema::plans::id;

    let mut connection = connection_without_transaction();

    let query = "Select * from plans"; // returns existing rows in table plans

    let result1:Result<Vec<Plan>, diesel::result::Error> = diesel::sql_query(query).get_results::<Plan>(&mut connection);
    
    dbg!(result1.unwrap());

    let query = "INSERT INTO plans (code) VALUES ('CC-1') RETURNING *"; // insert data into plans table column 'code' 
    let result2: Result<Vec<Plan>, diesel::result::Error> = diesel::sql_query(query).get_results::<Plan>(&mut connection);

    dbg!(result2.unwrap()); // result2 contains newly created rows in table plans.

}