public SqlNode visit(SqlIdentifier id) {
// First check for builtin functions which don't have parentheses,
// like "LOCALTIME".
final SqlCall call = SqlUtil.makeCall(getScope().getValidator().getOperatorTable(), id);
if (call != null) {
return call;
}
return getScope().fullyQualify(id).identifier;
}
/**
* Derives an alias for a node, and invents a mangled identifier if it cannot.
*
* <p>Examples:
*
* <ul>
* <li>Alias: "1 + 2 as foo" yields "foo"
* <li>Identifier: "foo.bar.baz" yields "baz"
* <li>Anything else yields "expr$<i>ordinal</i>"
* </ul>
*
* @return An alias, if one can be derived; or a synthetic alias "expr$<i>ordinal</i>" if ordinal
* < 0; otherwise null
*/
public static String getAlias(SqlNode node, int ordinal) {
switch (node.getKind()) {
case AS:
// E.g. "1 + 2 as foo" --> "foo"
return ((SqlCall) node).operand(1).toString();
case OVER:
// E.g. "bids over w" --> "bids"
return getAlias(((SqlCall) node).operand(0), ordinal);
case IDENTIFIER:
// E.g. "foo.bar" --> "bar"
return Util.last(((SqlIdentifier) node).names);
default:
if (ordinal < 0) {
return null;
} else {
return SqlUtil.deriveAliasFromOrdinal(ordinal);
}
}
}
/**
* Creates a character string literal from an {@link NlsString}.
*
* <p>If the string's charset and collation are not set, uses the system defaults.
*/
public RexLiteral makeCharLiteral(NlsString str) {
assert str != null;
RelDataType type = SqlUtil.createNlsStringType(typeFactory, str);
return makeLiteral(str, type, SqlTypeName.CHAR);
}
