bug: The data type Decimal returns different precision.

[haitaoguan]

Have you read the Contributing Guidelines on issues?

• [X] I have read the Contributing Guidelines on issues.

Please confirm if bug report does NOT exists already ?

• [X] I confirm there is no existing issue for this

Describe the problem

select CASE
         WHEN r.row_id IS NOT NULL THEN
          r.ex_rate
         ELSE
          1.0000
       END AS ex_rate
  from ct a
  LEFT JOIN ce r
    ON a.cur_id = r.cur_id
   AND r.deleted_flag = '0'
   AND r.using_flag = '1'
   AND r.inure_date <= now()
   AND (r.abate_date >= now() OR r.abate_date IS NULL)

......
|    1.00000000 |
|    1.00000000 |
|    1.00000000 |
|    1.00000000 |
|    1.00000000 |
+---------------+
1016 rows in set (0.03 sec)

Expected behavior

......
|        1.0000 |
|        1.0000 |
|        1.0000 |
|        1.0000 |
|        1.0000 |
+---------------+
1016 rows in set (0.00 sec)

How To Reproduce

No response

Environment

./mysqld Ver 5.7.36-StoneDB-v1.0.3 for Linux on x86_64 (build-) build information as follow: Repository address: https://github.com/stoneatom/stonedb.git:stonedb-5.7-dev Branch name: stonedb-5.7-dev Last commit ID: 2daac7c Last commit time: Date: Mon May 8 15:20:14 2023 +0800 Build time: Date: Mon May 8 16:35:52 CST 2023

Are you interested in submitting a PR to solve the problem?

• [X] Yes, I will!