Yu Lei

https://github.com/opencypher/openCypher/blob/18fc8baccb6ed4f2ccf08dd684c1566eaccbc648/grammar/basic-grammar.xml#L244-L251

Close #6042

`logictest` will mistake converting double quote `"` to single quote `'` in query when testing with http protocol

1

https://github.com/datafuselabs/databend/blob/43cbd00efd425c1c2eb42a1f3815282754b28873/tests/logictest/http_connector.py#L121-L129 cc @ZeaLoVe

Feature: LIMIT push down for new planner

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In some cases, it's possible to push the `LIMIT` operator down to reduce the data to be processed. Besides, `LIMIT` hint of `ReadDataSource` will affect the behavior of `Random` table...

Feature: Introduce `TopN` operator in new planner

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For a query with both `ORDER BY` and `LIMIT` clauses, we can translate it into `TopN` operator, which can leverage with selection algorithm.

Feature: Introduce `ConstTableScan` operator to accelerate table scan with no required columns

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Sometimes, we have to read data from a table while none of the columns will be used in the query. For example: - `select count(*) from t` - `select *...

Feature: Support empty statement in new planner

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Accept `/* foo bar */ ;` as `Statement::Empty` and then do nothing in execution.

ClickHouse http handler cannot report runtime error

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For example: ```sql create table t (a string); insert into t values('abc'); select cast(a as int) from t; -- Error, cannot cast 'abc' into a integer ``` This query will...

## Summary TPC-DS is a very challenging benchmark to evaluate OLAP ability of a database system, which involves close to a hundred of complicated SQL queries. It will be a...

For some invalid subqueries, we should raise reasonable error for them. - [ ] Subqueries with invalid outer reference from a grouping context: `select (select t.a from t1) from t...