/**
* 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).getOperands()[1].toString();
case OVER:
// E.g. "bids over w" --> "bids"
return getAlias(((SqlCall) node).getOperands()[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);
}
}
}
public int reduceExpr(int opOrdinal, List<Object> list) {
final SqlParserUtil.ToTreeListItem betweenNode =
(SqlParserUtil.ToTreeListItem) list.get(opOrdinal);
SqlOperator op = betweenNode.getOperator();
assert op == this;
// Break the expression up into expressions. For example, a simple
// expression breaks down as follows:
//
// opOrdinal endExp1
// | |
// a + b BETWEEN c + d AND e + f
// |_____| |_____| |_____|
// exp0 exp1 exp2
// Create the expression between 'BETWEEN' and 'AND'.
final SqlParserPos pos = ((SqlNode) list.get(opOrdinal + 1)).getParserPosition();
SqlNode exp1 = SqlParserUtil.toTreeEx(list, opOrdinal + 1, 0, SqlKind.AND);
if ((opOrdinal + 2) >= list.size()) {
SqlParserPos lastPos = ((SqlNode) list.get(list.size() - 1)).getParserPosition();
final int line = lastPos.getEndLineNum();
final int col = lastPos.getEndColumnNum() + 1;
SqlParserPos errPos = new SqlParserPos(line, col, line, col);
throw SqlUtil.newContextException(
errPos, EigenbaseResource.instance().BetweenWithoutAnd.ex());
}
final Object o = list.get(opOrdinal + 2);
if (!(o instanceof SqlParserUtil.ToTreeListItem)) {
SqlParserPos errPos = ((SqlNode) o).getParserPosition();
throw SqlUtil.newContextException(
errPos, EigenbaseResource.instance().BetweenWithoutAnd.ex());
}
if (((SqlParserUtil.ToTreeListItem) o).getOperator().getKind() != SqlKind.AND) {
SqlParserPos errPos = ((SqlParserUtil.ToTreeListItem) o).getPos();
throw SqlUtil.newContextException(
errPos, EigenbaseResource.instance().BetweenWithoutAnd.ex());
}
// Create the expression after 'AND', but stopping if we encounter an
// operator of lower precedence.
//
// For example,
// a BETWEEN b AND c + d OR e
// becomes
// (a BETWEEN b AND c + d) OR e
// because OR has lower precedence than BETWEEN.
SqlNode exp2 = SqlParserUtil.toTreeEx(list, opOrdinal + 3, getRightPrec(), SqlKind.OTHER);
// Create the call.
SqlNode exp0 = (SqlNode) list.get(opOrdinal - 1);
SqlCall newExp =
createCall(
betweenNode.getPos(),
exp0,
exp1,
exp2,
SqlLiteral.createSymbol(flag, SqlParserPos.ZERO));
// Replace all of the matched nodes with the single reduced node.
SqlParserUtil.replaceSublist(list, opOrdinal - 1, opOrdinal + 4, newExp);
// Return the ordinal of the new current node.
return opOrdinal - 1;
}
