sql (fix): Digit identifier must be quoted

[takezoe]

No description provided.

[xerial]

No need to quote this string representation

[xerial]

@takezoe I think DigitIdentifiers are intended for representing GROUP BY 1, 2, 3 .... In which case do we need to quote them?

[takezoe]

I think DigitIdentifiers are intended for representing GROUP BY 1, 2, 3 ...

Ah, I see.

In which case do we need to quote them?

Assuming the following query, "123" is parsed as a digit identifier

SELECT * FROM database."123"

and regenerated SQL from the AST will be invalid:

SELECT * FROM database.123

Now I found the root cause is that a digit identifier is generated in Expression.newIdentifier() for the table name when generate SQL. I will send another PR.

airframe/airframe-sql/src/main/scala/wvlet/airframe/sql/model/Expression.scala

Lines 459 to 472 in eb3c43e

	def newIdentifier(x: String): Identifier = {
	if (x.startsWith("`") && x.endsWith("`")) {
	BackQuotedIdentifier(x.stripPrefix("`").stripSuffix("`"), None)
	} else if (x.startsWith("\"") && x.endsWith("\"")) {
	QuotedIdentifier(x.stripPrefix("\"").stripSuffix("\""), None)
	} else if (x.matches("[0-9]+")) {
	DigitId(x, None)
	} else if (!x.matches("[0-9a-zA-Z_]*")) {
	// Quotations are needed with special characters to generate valid SQL
	QuotedIdentifier(x, None)
	} else {
	UnquotedIdentifier(x, None)
	}
	}

[takezoe]

Created #3493