can't create binding for union all statements

[zz-jason]

Bug Report

1. Minimal reproduce step (Required)

-- init table:
drop table if exists t;
create table t(a bigint, b bigint, index a(a));

-- create a global binding for union all statement:
create binding for
select * from t union all select * from t
using
select * from t use index(a) union all select * from t use index();

2. What did you expect to see? (Required)

created successfully.

3. What did you see instead (Required)

TiDB(root@127.0.0.1:test) > create binding for select * from t union all select * from t using select * from t use index(a) union all select * from t use index();
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your TiDB version for the right syntax to use line 1 column 40 near "union all select * from t using select * from t use index(a) union all select * from t use index()"

4. What is your TiDB version? (Required)

TiDB(root@127.0.0.1:test) > select tidb_version()\G
*************************** 1. row ***************************
tidb_version(): Release Version: v4.0.0-beta.2-1189-g7b6a5cdb7
Edition: Community
Git Commit Hash: 7b6a5cdb76dbf70d2ae2d01fa9b0fe0d6048ab88
Git Branch: master
UTC Build Time: 2020-09-09 09:03:38
GoVersion: go1.15
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false
1 row in set (0.00 sec)

[winoros]

The parser only dealed with SelectStmt while the UNION ALL is SetOprStmt

[rebelice]

/assign @rebelice

[sre-bot]

Integrity check:
RCA symptom trigger_condition affect_version fix_version fields are empty
@rebelice
Please comment /info to get template

[ti-srebot]

Please edit this comment to complete the following information

Not a bug

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2. Add notes to indicate why it is not a bug

Duplicate bug

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Bug

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Example for how to fill out the template: #20100

1. Root Cause Analysis (RCA)

2. Symptom

3. All Trigger Conditions

4. Workaround (optional)

5. Affected versions

6. Fixed versions

[rebelice]

Please edit this comment to complete the following information

Bug

1. Root Cause Analysis (RCA)

SQL BINDING only dealed with SelectStmt while the UNION ALL is SetOprStmt.

2. Symptom

You have an error in your SQL syntax.

3. All Trigger Conditions

Try to create binding for union all statements.

4. Workaround (optional)

5. Affected versions

[v4.0.0:v4.0.7]

6. Fixed versions

v4.0.8