- All Superinterfaces:
- All Known Implementing Classes:
public interface AggregatingScope
- extends SqlValidatorScope
An extension to the
SqlValidatorScope interface which indicates that
the scope is aggregating.
A scope which is aggregating must implement this interface. Such a scope
will return the same set of identifiers as its parent scope, but some of
those identifiers may not be accessible because they are not in the GROUP BY
- Mar 25, 2003
- $Id: //open/dev/farrago/src/org/eigenbase/sql/validate/AggregatingScope.java#9 $
Checks whether an expression is constant within the GROUP BY clause.
|Methods inherited from interface org.eigenbase.sql.validate.SqlValidatorScope
addChild, findAliases, findAllColumnNames, findQualifyingTableName, fullyQualify, getMonotonicity, getNode, getOperandScope, getOrderList, getValidator, lookupWindow, resolve, resolveColumn, validateExpr
boolean checkAggregateExpr(SqlNode expr,
- Checks whether an expression is constant within the GROUP BY clause. If
the expression completely matches an expression in the GROUP BY clause,
returns true. If the expression is constant within the group, but does
not exactly match, returns false. If the expression is not constant,
throws an exception. Examples:
- If we are 'f(b, c)' in 'SELECT a + f(b, c) FROM t GROUP BY a', then
the whole expression matches a group column. Return true.
- Just an ordinary expression in a GROUP BY query, such as 'f(SUM(a),
1, b)' in 'SELECT f(SUM(a), 1, b) FROM t GROUP BY b'. Returns false.
- Illegal expression, such as 'f(5, a, b)' in 'SELECT f(a, b) FROM t
GROUP BY a'. Throws when it enounters the 'b' operand, because it is not
in the group clause.