MySQL query does not return some rows

I have 3 tables as follow.

DATA(entity_id, crv_name, data_cnt_id)
PROCESSED_DATA(entity_id, crv_name, run_id)
RUNS(run_id, data_cnt_id)

Both DATA and PROCESSED_DATA have similar columns, except for the last one. PROCESSED_DATA also has significantly more rows than DATA.

DATA is about old crv_name values, and PROCESSED_DATA contains new crv_name values.

I am trying to write a query which would return something like this, for a specific run (identified with RUN_ID in PROCESSED_DATA and RUNS and with DATA_CNT_ID in DATA) :

+----------------------------------------------------------------+
| PROCESSED_DATA.ENTITY_ID PROCESSED_DATA.CRV_NAME DATA.CRV_NAME |
+----------------------------------------------------------------+
| entity123                  123_new_name           123_old_name |
| entity456                  456_new_name           456_old_name |
| entity789                  789_new_name           null         |
+----------------------------------------------------------------+

However, I can't get that last row (ie an entity which doesn't have an old crv_name, and therefore is not present in the table DATA) with my query below :

select pd.entity_id, pd.crv_name, d.crv_name
from processed_data pd
join data d on d.entity_id = pd.entity_id
join runs r on r.run_id = pd.run_id and r.data_cnt_id = d.data_cnt_id
where r.run_id = 7

Could you help me to improve my query ?

---

You need to outer join the records:

select pd.ntt_id, pd.crv_name, d.crv_name
from processed_data pd
left join data d on d.entity_id = pd.entity_id
left join runs r on r.run_id = pd.run_id and r.data_cnt_id = d.data_cnt_id and r.run_id = 7;

In case there must be a run 7:

select pd.ntt_id, pd.crv_name, d.crv_name
from processed_data pd
inner join runs r on r.run_id = pd.run_id and r.run_id = 7
left join data d on d.entity_id = pd.entity_id and d.data_cnt_id = r.data_cnt_id;