Wei-hao-Li commented on code in PR #14928:
URL: https://github.com/apache/iotdb/pull/14928#discussion_r1992969042
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iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/relational/analyzer/StatementAnalyzer.java:
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@@ -1077,6 +1134,789 @@ private List<Expression>
analyzeSelect(QuerySpecification node, Scope scope) {
return outputExpressionBuilder.build();
}
+ /**
+ * Check if there is Columns function in expression, and verify they are
same if there are multi
+ * Column functions.
+ *
+ * @param expression input expression
+ * @return if there is Columns function in expression
+ * @throws SemanticException if there are multi Columns functions but
different
+ */
+ private boolean containsColumns(Expression expression) {
+ return containsColumnsHelper(expression) != null;
+ }
+
+ private Node containsColumnsHelper(Node node) {
+ if (node instanceof Columns) {
+ return node;
+ }
+
+ Node target = null;
+ for (Node child : node.getChildren()) {
+ Node childResult = containsColumnsHelper(child);
+
+ if (childResult == null) {
+ continue;
+ }
+
+ // initialize target
+ if (target == null) {
+ target = childResult;
+ continue;
+ }
+
+ if (!childResult.equals(target)) {
+ throw new SemanticException(
+ "Multiple different COLUMNS in the same expression are not
supported");
+ }
+ }
+ return target;
+ }
+
+ private class ExpandColumnsVisitor extends AstVisitor<List<Expression>,
Scope> {
+ private final Identifier alias;
+ // Record Columns expanded result in process, not always equals with
final result
+ private List<Expression> expandedExpressions;
+ // Records the actual output column name of each Expression, used to
compute output Scope.
+ private List<String> accordingColumnNames;
+
+ private ExpandColumnsVisitor(Identifier alias) {
+ this.alias = alias;
+ }
+
+ public List<String> getAccordingColumnNames() {
+ return accordingColumnNames;
+ }
+
+ protected List<Expression> visitNode(Node node, Scope scope) {
+ throw new UnsupportedOperationException(
+ "This Visitor only supported process of Expression");
+ }
+
+ protected List<Expression> visitExpression(Expression node, Scope scope)
{
+ if (node.getChildren().isEmpty()) {
+ return Collections.singletonList(node);
+ }
+ throw new UnsupportedOperationException("UnSupported Expression: " +
node);
+ }
+
+ @Override
+ public List<Expression> visitColumns(Columns node, Scope context) {
+ // avoid redundant process
+ if (expandedExpressions != null) {
+ return expandedExpressions;
+ }
+
+ context.getRelationType().getVisibleFields();
Review Comment:
> Remove this line?
Yes, it's a typo
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