/** * Creates a relational expression which projects an array of expressions, and optionally * optimizes. * * <p>The result may not be a {@link ProjectRel}. If the projection is trivial, <code>child</code> * is returned directly; and future versions may return other formulations of expressions, such as * {@link CalcRel}. * * @param child input relational expression * @param exprs list of expressions for the input columns * @param fieldNames aliases of the expressions, or null to generate * @param optimize Whether to return <code>child</code> unchanged if the projections are trivial. */ public static RelNode createProject( RelNode child, List<RexNode> exprs, List<String> fieldNames, boolean optimize) { final RelOptCluster cluster = child.getCluster(); final RexProgram program = RexProgram.create(child.getRowType(), exprs, null, fieldNames, cluster.getRexBuilder()); final List<RelCollation> collationList = program.getCollations(child.getCollationList()); if (DeprecateProjectAndFilter) { return new CalcRel( cluster, child.getTraitSet(), child, program.getOutputRowType(), program, collationList); } else { final RelDataType rowType = RexUtil.createStructType(cluster.getTypeFactory(), exprs, fieldNames); if (optimize && RemoveTrivialProjectRule.isIdentity(exprs, rowType, child.getRowType())) { return child; } return new ProjectRel( cluster, cluster.traitSetOf( collationList.isEmpty() ? RelCollationImpl.EMPTY : collationList.get(0)), child, exprs, rowType, ProjectRelBase.Flags.Boxed); } }
/** * Creates a relational expression which projects an array of expressions, and optionally * optimizes. * * <p>The result may not be a {@link ProjectRel}. If the projection is trivial, <code>child</code> * is returned directly; and future versions may return other formulations of expressions, such as * {@link CalcRel}. * * @param child input relational expression * @param exprs list of expressions for the input columns * @param fieldNames aliases of the expressions, or null to generate * @param optimize Whether to return <code>child</code> unchanged if the projections are trivial. */ public static RelNode createProject( RelNode child, List<RexNode> exprs, List<String> fieldNames, boolean optimize) { final RelOptCluster cluster = child.getCluster(); final RexProgram program = RexProgram.create(child.getRowType(), exprs, null, fieldNames, cluster.getRexBuilder()); final List<RelCollation> collationList = program.getCollations(child.getCollationList()); if (DEPRECATE_PROJECT_AND_FILTER) { return new CalcRel( cluster, child.getTraitSet(), child, program.getOutputRowType(), program, collationList); } else { final RelDataType rowType = RexUtil.createStructType( cluster.getTypeFactory(), exprs, fieldNames == null ? null : SqlValidatorUtil.uniquify(fieldNames, SqlValidatorUtil.F_SUGGESTER)); if (optimize && RemoveTrivialProjectRule.isIdentity(exprs, rowType, child.getRowType())) { return child; } return new ProjectRel( cluster, cluster.traitSetOf( collationList.isEmpty() ? RelCollationImpl.EMPTY : collationList.get(0)), child, exprs, rowType, ProjectRelBase.Flags.BOXED); } }