Support DISCARD [ALL | PLANS | SEQUENCES | TEMPORARY | TEMP]

[gandronchik]

DISCARD [ALL | PLANS | SEQUENCES | TEMPORARY | TEMP]

[coveralls]

Pull Request Test Coverage Report for Build 2344825331

• 33 of 36 (91.67%) changed or added relevant lines in 3 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage increased (+0.005%) to 90.49%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/parser.rs	11	14	78.57%

Files with Coverage Reduction	New Missed Lines	%
src/ast/mod.rs	1	78.17%

Totals
Change from base Build 2328175823:	0.005%
Covered Lines:	8335
Relevant Lines:	9211

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💛 - Coveralls

[alamb]

Reference: https://www.postgresql.org/docs/current/sql-discard.html#:~:text=Description,and%20also%20resets%20additional%20state.

Thank you @gandronchik