qualified column name should be multipartIdentifier.

Author: viirya

sql/catalyst/src/main/antlr4/org/apache/spark/sql/catalyst/parser/SqlBase.g4

@@ -149,7 +149,7 @@ statement
     | ALTER (TABLE | VIEW) multipartIdentifier
         UNSET TBLPROPERTIES (IF EXISTS)? tablePropertyList             #unsetTableProperties
     | ALTER TABLE multipartIdentifier
-        (ALTER | CHANGE) COLUMN? qualifiedName
+        (ALTER | CHANGE) COLUMN? multipartIdentifier
         (TYPE dataType)? (COMMENT comment=STRING)? colPosition?        #alterTableColumn
     | ALTER TABLE multipartIdentifier (partitionSpec)?
         SET SERDE STRING (WITH SERDEPROPERTIES tablePropertyList)?     #setTableSerDe

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/parser/AstBuilder.scala

@@ -2677,9 +2677,12 @@ class AstBuilder(conf: SQLConf) extends SqlBaseBaseVisitor[AnyRef] with Logging
       operationNotAllowed(s"ALTER TABLE table $verb COLUMN requires a TYPE or a COMMENT", ctx)
     }
 
+    val tableIdentifier = ctx.multipartIdentifier(0)
+    val qualifiedColumn = ctx.multipartIdentifier(1)
+
     AlterTableAlterColumnStatement(
-      visitMultipartIdentifier(ctx.multipartIdentifier),
-      typedVisit[Seq[String]](ctx.qualifiedName),
+      visitMultipartIdentifier(tableIdentifier),
+      typedVisit[Seq[String]](qualifiedColumn),
       Option(ctx.dataType).map(typedVisit[DataType]),
       Option(ctx.comment).map(string))
   }

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/parser/ErrorParserSuite.scala

@@ -95,7 +95,7 @@ class ErrorParserSuite extends AnalysisTest {
       """
         |ALTER TABLE t
         |CHANGE COLUMN
-        |test-col BIGINT
+        |test-col TYPE BIGINT
       """.stripMargin, 4, 4, 5, msg + " test-col")
     intercept("CREATE TABLE test (attri-bute INT)", 1, 24, 25, msg + " attri-bute")
     intercept(