Support CEIL(expr TO DateTimeField) and FLOOR(expr TO DateTimeField)

[sarahyurick]

Hi, I'd like to be able to parse the following statements:

SELECT CEIL(d TO DAY) FROM df
SELECT CEIL(d TO HOUR) FROM df
SELECT CEIL(d TO MINUTE) FROM df
SELECT CEIL(d TO SECOND) FROM df
SELECT CEIL(d TO MILLISECOND) FROM df

and

SELECT FLOOR(d TO DAY) FROM df
SELECT FLOOR(d TO HOUR) FROM df
SELECT FLOOR(d TO MINUTE) FROM df
SELECT FLOOR(d TO SECOND) FROM df
SELECT FLOOR(d TO MILLISECOND) FROM df

I also added Microsecond and Millisecond in addition to the existing (plural) Microseconds and Milliseconds.

[coveralls]

Pull Request Test Coverage Report for Build 3199394745

• 55 of 60 (91.67%) changed or added relevant lines in 4 files are covered.
• 717 unchanged lines in 4 files lost coverage.
• Overall coverage increased (+0.06%) to 85.663%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/ast/value.rs	2	3	66.67%
src/parser.rs	20	22	90.91%
tests/sqlparser_common.rs	24	26	92.31%

Files with Coverage Reduction	New Missed Lines	%
src/ast/data_type.rs	11	88.04%
tests/sqlparser_common.rs	44	97.05%
src/ast/mod.rs	253	77.47%
src/parser.rs	409	83.16%

Totals
Change from base Build 3146760243:	0.06%
Covered Lines:	10319
Relevant Lines:	12046

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💛 - Coveralls

[alamb]

Thank you for the contribution @sarahyurick -- what database supports the CEIL( as date) syntax?

Do you think this will cause issues with existing queries that use ceil as a function, for example

select ceil(float_column) from my_table;

?

[sarahyurick]

Thank you for the contribution @sarahyurick -- what database supports the CEIL( as date) syntax?

Do you think this will cause issues with existing queries that use ceil as a function, for example

select ceil(float_column) from my_table;

?

In terms of other databases that support this syntax, I've had trouble finding examples, but am mostly trying to support existing tests in Dask-SQL that were originally implemented with dask-contrib/dask-sql#91.

I can create some tests with CEIL(float_column) to try to gauge possible issues there.

[alamb]

I can create some tests with CEIL(float_column) to try to gauge possible issues there.

As long as CEIL(float_column) can be parsed as a function call to CEIL I think it would be a good addition. Thank you

[sarahyurick]

Okay @alamb, let me know what you think of this implementation.

I created a special DateTimeField::NoDateTime and then, depending on whether or not the TO keyword is there, we construct Expr::Ceil/Expr::Floor accordingly.

Similarly, when we're formatting the expression, we check if we have a DateTimeField::NoDateTime, which means that it should be formatted as CEIL(x), else it should be formatted as CEIL(expr TO DateTimeField).

[alamb]

Thank you @sarahyurick -- I think this PR looks almost ready to go. I had a few style suggestions, but I think the basic structure looks good as do the tests. Thank you.

[sarahyurick]

OK, I've refactored parse_ceil_expr and parse_floor_expr into parse_ceil_floor_expr. Let me know what you think.