/** Returns whether a {@link RexProgram} contains expressions which require decimal expansion. */
public static boolean requiresDecimalExpansion(RexProgram program, boolean recurse) {
final List<RexNode> exprList = program.getExprList();
for (RexNode expr : exprList) {
if (requiresDecimalExpansion(expr, recurse)) {
return true;
}
}
return false;
}
public void onMatch(RelOptRuleCall call) {
CalcRel calc = (CalcRel) call.getRels()[0];
RexProgram program = calc.getProgram();
final List<RexNode> exprList = program.getExprList();
// Form a list of expressions with sub-expressions fully
// expanded.
final List<RexNode> expandedExprList = new ArrayList<RexNode>(exprList.size());
final RexShuttle shuttle =
new RexShuttle() {
public RexNode visitLocalRef(RexLocalRef localRef) {
return expandedExprList.get(localRef.getIndex());
}
};
for (RexNode expr : exprList) {
expandedExprList.add(expr.accept(shuttle));
}
if (reduceExpressions(calc, expandedExprList)) {
final RexProgramBuilder builder =
new RexProgramBuilder(
calc.getChild().getRowType(), calc.getCluster().getRexBuilder());
List<RexLocalRef> list = new ArrayList<RexLocalRef>();
for (RexNode expr : expandedExprList) {
list.add(builder.registerInput(expr));
}
if (program.getCondition() != null) {
final int conditionIndex = program.getCondition().getIndex();
final RexNode newConditionExp = expandedExprList.get(conditionIndex);
if (newConditionExp.isAlwaysTrue()) {
// condition is always TRUE - drop it
} else if ((newConditionExp instanceof RexLiteral)
|| RexUtil.isNullLiteral(newConditionExp, true)) {
// condition is always NULL or FALSE - replace calc
// with empty
call.transformTo(new EmptyRel(calc.getCluster(), calc.getRowType()));
return;
} else {
builder.addCondition(list.get(conditionIndex));
}
}
int k = 0;
for (RexLocalRef projectExpr : program.getProjectList()) {
final int index = projectExpr.getIndex();
builder.addProject(
list.get(index).getIndex(),
program.getOutputRowType().getFieldList().get(k++).getName());
}
call.transformTo(
new CalcRel(
calc.getCluster(),
calc.getTraits(),
calc.getChild(),
calc.getRowType(),
builder.getProgram(),
calc.getCollationList()));
// New plan is absolutely better than old plan.
call.getPlanner().setImportance(calc, 0.0);
}
}
/** Converts an expression from {@link RexNode} to {@link SqlNode} format. */
SqlNode toSql(RexProgram program, RexNode rex) {
if (rex instanceof RexLocalRef) {
final int index = ((RexLocalRef) rex).getIndex();
return toSql(program, program.getExprList().get(index));
} else if (rex instanceof RexInputRef) {
return field(((RexInputRef) rex).getIndex());
} else if (rex instanceof RexLiteral) {
final RexLiteral literal = (RexLiteral) rex;
switch (literal.getTypeName().getFamily()) {
case CHARACTER:
return SqlLiteral.createCharString((String) literal.getValue2(), POS);
case NUMERIC:
case EXACT_NUMERIC:
return SqlLiteral.createExactNumeric(literal.getValue().toString(), POS);
case APPROXIMATE_NUMERIC:
return SqlLiteral.createApproxNumeric(literal.getValue().toString(), POS);
case BOOLEAN:
return SqlLiteral.createBoolean((Boolean) literal.getValue(), POS);
case DATE:
return SqlLiteral.createDate((Calendar) literal.getValue(), POS);
case TIME:
return SqlLiteral.createTime(
(Calendar) literal.getValue(), literal.getType().getPrecision(), POS);
case TIMESTAMP:
return SqlLiteral.createTimestamp(
(Calendar) literal.getValue(), literal.getType().getPrecision(), POS);
case ANY:
switch (literal.getTypeName()) {
case NULL:
return SqlLiteral.createNull(POS);
// fall through
}
default:
throw new AssertionError(literal + ": " + literal.getTypeName());
}
} else if (rex instanceof RexCall) {
final RexCall call = (RexCall) rex;
final SqlOperator op = call.getOperator();
final List<SqlNode> nodeList = toSql(program, call.getOperands());
if (op == SqlStdOperatorTable.CAST) {
RelDataType type = call.getType();
if (type.getSqlTypeName() == SqlTypeName.VARCHAR
&& dialect.getDatabaseProduct() == SqlDialect.DatabaseProduct.MYSQL) {
// MySQL doesn't have a VARCHAR type, only CHAR.
nodeList.add(
new SqlDataTypeSpec(
new SqlIdentifier("CHAR", POS), type.getPrecision(), -1, null, null, POS));
} else {
nodeList.add(toSql(type));
}
}
if (op == SqlStdOperatorTable.CASE) {
final SqlNode valueNode;
final List<SqlNode> whenList = Expressions.list();
final List<SqlNode> thenList = Expressions.list();
final SqlNode elseNode;
if (nodeList.size() % 2 == 0) {
// switched:
// "case x when v1 then t1 when v2 then t2 ... else e end"
valueNode = nodeList.get(0);
for (int i = 1; i < nodeList.size() - 1; i += 2) {
whenList.add(nodeList.get(i));
thenList.add(nodeList.get(i + 1));
}
} else {
// other: "case when w1 then t1 when w2 then t2 ... else e end"
valueNode = null;
for (int i = 0; i < nodeList.size() - 1; i += 2) {
whenList.add(nodeList.get(i));
thenList.add(nodeList.get(i + 1));
}
}
elseNode = nodeList.get(nodeList.size() - 1);
return op.createCall(
POS,
valueNode,
new SqlNodeList(whenList, POS),
new SqlNodeList(thenList, POS),
elseNode);
}
if (op instanceof SqlBinaryOperator && nodeList.size() > 2) {
// In RexNode trees, OR and AND have any number of children;
// SqlCall requires exactly 2. So, convert to a left-deep binary tree.
return createLeftCall(op, nodeList);
}
return op.createCall(new SqlNodeList(nodeList, POS));
} else {
throw new AssertionError(rex);
}
}