xianyinxin commented on a change in pull request #26167: [SPARK-28893][SQL]
Support MERGE INTO in the parser and add the corresponding logical plan
URL: https://github.com/apache/spark/pull/26167#discussion_r344010635
##########
File path:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/parser/AstBuilder.scala
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@@ -395,6 +395,123 @@ class AstBuilder(conf: SQLConf) extends
SqlBaseBaseVisitor[AnyRef] with Logging
predicate)
}
+ private def withAssignments(
+ assignCtx: SqlBaseParser.AssignmentListContext): (Seq[Expression],
Seq[Expression]) =
+ withOrigin(assignCtx) {
+ assignCtx.assignment().asScala.map { assign =>
+ (UnresolvedAttribute(visitQualifiedName(assign.key)),
expression(assign.value))
+ }.foldLeft(Seq[Expression](), Seq[Expression]()) {
+ case (a, b) => (a._1 :+ b._1, a._2 :+ b._2)
+ }
+ }
+
+ override def visitMergeIntoTable(ctx: MergeIntoTableContext): LogicalPlan =
withOrigin(ctx) {
+ val targetTable = UnresolvedRelation(visitMultipartIdentifier(ctx.target))
+ val targetTableAlias = if (ctx.targetAlias != null) {
+ val ident = ctx.targetAlias.strictIdentifier()
+ // We do not allow columns aliases after table alias.
+ if (ctx.targetAlias.identifierList() != null) {
+ throw new ParseException("Columns aliases is not allowed in MERGE.",
+ ctx.targetAlias.identifierList())
+ }
+ if (ident != null) Some(ident.getText) else None
+ } else {
+ None
+ }
+ val aliasedTarget = targetTableAlias.map(SubqueryAlias(_,
targetTable)).getOrElse(targetTable)
+
+ val sourceTableOrQuery = if (ctx.source != null) {
+ UnresolvedRelation(visitMultipartIdentifier(ctx.source))
+ } else if (ctx.sourceQuery != null) {
+ visitQuery(ctx.sourceQuery)
+ } else {
+ throw new ParseException("Empty source for merge: you should specify a
source" +
+ " table/subquery in merge.", ctx.source)
+ }
+ val sourceTableAlias = if (ctx.sourceAlias != null) {
+ val ident = ctx.sourceAlias.strictIdentifier()
+ // We do not allow columns aliases after table alias.
+ if (ctx.sourceAlias.identifierList() != null) {
+ throw new ParseException("Columns aliases is not allowed in MERGE.",
+ ctx.sourceAlias.identifierList())
+ }
+ if (ident != null) Some(ident.getText) else None
+ } else {
+ None
+ }
+ val aliasedSource =
+ sourceTableAlias.map(SubqueryAlias(_,
sourceTableOrQuery)).getOrElse(sourceTableOrQuery)
+
+ val mergeCondition = expression(ctx.mergeCondition)
+
+ val matchedClauses = ctx.matchedClause()
+ if (matchedClauses.size() > 2) {
+ throw new ParseException("There should be at most 2 'WHEN MATCHED'
clauses.",
+ matchedClauses.get(2))
+ }
+ val matchedActions = matchedClauses.asScala.map {
+ clause => {
+ if (clause.matchedAction().DELETE() != null) {
+ DeleteAction(
+ if (clause.matchedCond != null)
Some(expression(clause.matchedCond)) else None)
+ } else if (clause.matchedAction().UPDATE() != null) {
+ val (setColumns, setValues): (Seq[Expression], Seq[Expression]) =
+ if (clause.matchedAction().ASTERISK() != null) {
Review comment:
done
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