/**
* Flatten this FSqry into the outer query block. The steps in flattening are: o Mark all
* ResultColumns as redundant, so that they are "skipped over" at generate(). o Append the
* wherePredicates to the outer list. o Return the fromList so that the caller will merge the 2
* lists RESOLVE - FSqrys with subqueries are currently not flattenable. Some of them can be
* flattened, however. We need to merge the subquery list when we relax this restriction.
*
* <p>NOTE: This method returns NULL when flattening RowResultSetNodes (the node for a VALUES
* clause). The reason is that no reference is left to the RowResultSetNode after flattening is
* done - the expressions point directly to the ValueNodes in the RowResultSetNode's
* ResultColumnList.
*
* @param rcl The RCL from the outer query
* @param outerPList PredicateList to append wherePredicates to.
* @param sql The SubqueryList from the outer query
* @param gbl The group by list, if any
* @param havingClause The HAVING clause, if any
* @return FromList The fromList from the underlying SelectNode.
* @exception StandardException Thrown on error
*/
public FromList flatten(
ResultColumnList rcl,
PredicateList outerPList,
SubqueryList sql,
GroupByList gbl,
ValueNode havingClause)
throws StandardException {
FromList fromList = null;
SelectNode selectNode;
resultColumns.setRedundant();
subquery.getResultColumns().setRedundant();
/*
** RESOLVE: Each type of result set should know how to remap itself.
*/
if (subquery instanceof SelectNode) {
selectNode = (SelectNode) subquery;
fromList = selectNode.getFromList();
// selectNode.getResultColumns().setRedundant();
if (selectNode.getWherePredicates().size() > 0) {
outerPList.destructiveAppend(selectNode.getWherePredicates());
}
if (selectNode.getWhereSubquerys().size() > 0) {
sql.destructiveAppend(selectNode.getWhereSubquerys());
}
} else if (!(subquery instanceof RowResultSetNode)) {
if (SanityManager.DEBUG) {
SanityManager.THROWASSERT(
"subquery expected to be either a SelectNode or a RowResultSetNode, but is a "
+ subquery.getClass().getName());
}
}
/* Remap all ColumnReferences from the outer query to this node.
* (We replace those ColumnReferences with clones of the matching
* expression in the SELECT's RCL.
*/
rcl.remapColumnReferencesToExpressions();
outerPList.remapColumnReferencesToExpressions();
if (gbl != null) {
gbl.remapColumnReferencesToExpressions();
}
if (havingClause != null) {
havingClause.remapColumnReferencesToExpressions();
}
return fromList;
}
/**
* Prints the sub-nodes of this object. See QueryTreeNode.java for how tree printing is supposed
* to work.
*
* @param depth The depth of this node in the tree
*/
public void printSubNodes(int depth) {
super.printSubNodes(depth);
if (methodCall != null) {
printLabel(depth, "methodCall: ");
methodCall.treePrint(depth + 1);
}
if (exposedName != null) {
printLabel(depth, "exposedName: ");
exposedName.treePrint(depth + 1);
}
if (subqueryList != null) {
printLabel(depth, "subqueryList: ");
subqueryList.treePrint(depth + 1);
}
}
