MySQL does not select all data from one table that is Left Join with another table?

Asked Dec 30 '17 at 08:33

Active Dec 30 '17 at 13:19

Viewed 47 times

In one of my PHP application, I use left join between two MySQL tables using the following query:

SELECT bs.question_code, bs.question_english, count( st.id ) sqid
FROM bs_qbank_question bs
LEFT JOIN bs_qbank_question_study_link st
  ON bs.id = st.question_id

The problem is, it selects only those rows from bs_qbank_question that have at least one row in bs_qbank_question_study_link table. If there is no data for a particular row of bs_qbank_question in bs_qbank_question_study_link then that row is not selected.

But I need to select each row from bs_qbank_question and also need one column for each row from bs_qbank_question_study_link as count the total occurrence of that row.

Can anyone tell me what's wrong with my query and how can I replace count( st.id ) as 0 if there is no data for any row?
- Thanks

edited Dec 30 '17 at 13:19

Nico Haase

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asked Dec 30 '17 at 08:33

Shimul

3

join outer https://stackoverflow.com/a/38578/2845029 – aarosil Dec 30 '17 at 08:36
2

and also add group by at end of the query for eg: **GROUP BY bs.question_code,bs.question_english** – maddy23285 Dec 30 '17 at 08:44
See COALESCE(). – Strawberry Dec 30 '17 at 09:38

MySQL does not select all data from one table that is Left Join with another table?

0 Answers0