Support CREATE OR REPLACE TABLE

[HuSen8891]

Which issue does this PR close?

Closes #2605

Rationale for this change

replace the table content if table already exits
❯ create table xx as values(1,2),(3,4);
+---------+---------+
| column1 | column2 |
+---------+---------+
| 1 | 2 |
| 3 | 4 |
+---------+---------+
2 rows in set. Query took 0.004 seconds.

❯ create or replace table xx as values(5,6);
+---------+---------+
| column1 | column2 |
+---------+---------+
| 5 | 6 |
+---------+---------+
1 row in set. Query took 0.004 seconds.

if 'if not exists' and 'or replace' are both specified, treat as 'or replace'
❯ create or replace table if not exists xx as values(7,8);
+---------+---------+
| column1 | column2 |
+---------+---------+
| 7 | 8 |
+---------+---------+
1 row in set. Query took 0.002 seconds.

What changes are included in this PR?

adjust rules for create table in context.rs

[Ted-Jiang]

@AssHero Thanks for your work 👍
Maybe you can add some test like
https://github.com/apache/arrow-datafusion/blob/0c4ffd4f7b064a8f4e4a167e2e4c913389056968/datafusion/core/tests/sql/create_drop.rs#L22-L46

[waynexia]

if 'if not exists' and 'or replace' are both specified, treat as 'or replace'

I personally feel weird about IF NOT EXIST coexist with OR REPLACE. They are asking for two different behaviors. Should we reject this kind of query like others ( 1, 2 )?

[HuSen8891]

@AssHero Thanks for your work 👍 Maybe you can add some test like

https://github.com/apache/arrow-datafusion/blob/0c4ffd4f7b064a8f4e4a167e2e4c913389056968/datafusion/core/tests/sql/create_drop.rs#L22-L46

ok, i'll add some test cases

[HuSen8891]

if 'if not exists' and 'or replace' are both specified, treat as 'or replace'

I personally feel weird about IF NOT EXIST coexist with OR REPLACE. They are asking for two different behaviors. Should we reject this kind of query like others ( 1, 2 )?

'create or replace if not exists' is not supported in MySQL/PG, and is not permitted in databricks.
we can have a disscussion about how to deal with it.

[andygrove]

Thanks for the contribution @AssHero. I also would like to see IF NOT EXISTS and OR REPLACE as separate options that cannot be used together. LGTM otherwise.

[HuSen8891]

Thanks for the contribution @AssHero. I also would like to see IF NOT EXISTS and OR REPLACE as separate options that cannot be used together. LGTM otherwise.

I'll separate the 'IF NOT EXISTS' and 'OR REPLACE', and report the error if both specified.

[alamb]

Looks great -- thank you @AssHero, @Ted-Jiang and @waynexia