liun03

Results 8 issues of liun03

## BigQuery ### Syntax and data Metric tables: - [x] parser: make sure the statement includes metric only. https://github.com/Canner/canner-metric-layer/pull/214 - [x] sql rewrite: rewrite statement and query duckdb with pre-aggregation...

Based on concept https://duckdb.org/docs/sql/data_types/numeric.html#fixed-point-decimals: We sense the decimal type in duckdb is based on int. BUT, there are some decimal issues with int based values: https://issues.apache.org/jira/browse/HIVE-21987 We need to follow...

Given `select * from my_table where date_time_field = ?` AND using prepared statement to query it WHEN we try to describe the statement and get the metadata info (column metadata)...

Create a proper test for pre-aggregation refreshing see https://github.com/Canner/canner-metric-layer/pull/252

We remove temp files and stale cache table one by one after creating or refreshing pre-aggregation currently. Maybe we can use a scheduler to clean those unused items.

Query InPredicate failed ``` select custkey, revenue from Revenue where custkey in (select custkey from Customer) limit 100 ```

Query union failed: ``` select custkey, revenue from Revenue union select custkey, revenue from Revenue limit 100 ```

In GoogleSQL(BigQuery), [lexical#case_sensitivity](https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical#case_sensitivity) Column names are case-insensitive and Table names are not always case-sensitive. Need to take care of it.