Redshift: CREATE TABLE ... (LIKE ..)

[yoavcloud]

Add support for Redshift CREATE TABLE new_table (LIKE parent_table [ { INCLUDING | EXCLUDING } DEFAULTS ])

[iffyio]

Suggested change

	NotParenthesized(CreateTableLike),
	Plain(CreateTableLike),

Thinking we can do similar to e.g. CreateTableOptions, so that NotParenthesized doesn't become ambiguous if there happens to be a third variant in the future

[iffyio]

Suggested change

	/// Specifies how to create a new table based on an existing table's schema.
	///
	/// Not parenthesized:
	/// '''sql
	/// CREATE TABLE new LIKE old ...
	/// '''
	/// [Snowflake](https://docs.snowflake.com/en/sql-reference/sql/create-table#label-create-table-like)
	/// [BigQuery](https://cloud.google.com/bigquery/docs/reference/standard-sql/data-definition-language#create_table_like)
	///
	/// Parenthesized:
	/// '''sql
	/// CREATE TABLE new (LIKE old ...)
	/// '''
	/// [Redshift](https://docs.aws.amazon.com/redshift/latest/dg/r_CREATE_TABLE_NEW.html)
	#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
	#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
	#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
	pub enum CreateTableLikeKind {
	Parenthesized(CreateTableLike),
	NotParenthesized(CreateTableLike),
	/// Specifies how to create a new table based on an existing table's schema.
	///
	/// '''sql
	/// CREATE TABLE new LIKE old ...
	/// '''
	#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
	#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
	#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
	pub enum CreateTableLikeKind {
	/// '''sql
	/// CREATE TABLE new (LIKE old ...)
	/// '''
	/// [Redshift](https://docs.aws.amazon.com/redshift/latest/dg/r_CREATE_TABLE_NEW.html)
	Parenthesized(CreateTableLike),
	/// '''sql
	/// CREATE TABLE new LIKE old ...
	/// '''
	/// [Snowflake](https://docs.snowflake.com/en/sql-reference/sql/create-table#label-create-table-like)
	/// [BigQuery](https://cloud.google.com/bigquery/docs/reference/standard-sql/data-definition-language#create_table_like)
	NotParenthesized(CreateTableLike),

Thinking something like this to document each variant with its example?

[iffyio]

Suggested change

	fn supports_create_table_like_in_parens(&self) -> bool {
	fn supports_create_table_like_parenthesized(&self) -> bool {

[iffyio]

Can we pull the logic out to a function like maybe_parse_create_table_like()? since it now adds a bit of code to the existing function

[iffyio]

LGTM! Thanks @yoavcloud!
cc @alamb