From 0786c6a74fc5ad5b9622ff253678817db0b42612 Mon Sep 17 00:00:00 2001
From: Shujing Yang <shujing.yang@databricks.com>
Date: Tue, 23 Sep 2025 17:38:12 -0700
Subject: [PATCH] init

---
 .../spark/sql/execution/command/tables.scala  | 11 +++++---
 .../command/v1/DescribeTableSuite.scala       | 28 +++++++++++++++++++
 2 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/command/tables.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/command/tables.scala
index d5dd934af2be1..73c3fe6ac17ca 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/command/tables.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/command/tables.scala
@@ -838,6 +838,13 @@ case class DescribeColumnCommand(
       Row("data_type", dataType),
       Row("comment", comment.getOrElse("NULL"))
     )
+
+    // show default value if present
+    val defaultKey = CURRENT_DEFAULT_COLUMN_METADATA_KEY
+    if (field.metadata.contains(defaultKey)) {
+      buffer += Row("default", field.metadata.getString(defaultKey))
+    }
+
     if (isExtended) {
       // Show column stats when EXTENDED or FORMATTED is specified.
       buffer += Row("min", cs.flatMap(_.min.map(
@@ -854,10 +861,6 @@ case class DescribeColumnCommand(
         hist <- c.histogram
       } yield histogramDescription(hist)
       buffer ++= histDesc.getOrElse(Seq(Row("histogram", "NULL")))
-      val defaultKey = CURRENT_DEFAULT_COLUMN_METADATA_KEY
-      if (field.metadata.contains(defaultKey)) {
-        buffer += Row("default", field.metadata.getString(defaultKey))
-      }
     }
     buffer.toSeq
   }
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/execution/command/v1/DescribeTableSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/execution/command/v1/DescribeTableSuite.scala
index f07dcea6b30e6..e0541f41d42f7 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/execution/command/v1/DescribeTableSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/execution/command/v1/DescribeTableSuite.scala
@@ -237,6 +237,34 @@ trait DescribeTableSuiteBase extends command.DescribeTableSuiteBase
     }
   }
 
+  test("DESCRIBE table_name column_name should show default value") {
+    withTable("t") {
+      sql(s"""CREATE TABLE t(
+        |  id INT,
+        |  name STRING COMMENT 'name column' DEFAULT 'default',
+        |  value DOUBLE
+        |) $defaultUsing""".stripMargin)
+      val descriptionDf = sql("DESCRIBE t name")
+      QueryTest.checkAnswer(
+        descriptionDf,
+        Seq(
+          Row("col_name", "name"),
+          Row("data_type", "string"),
+          Row("comment", "name column"),
+          Row("default", "'default'")))
+    }
+  }
+
+  test("DESCRIBE EXTENDED table_name column_name should not duplicate default value") {
+    withTable("t") {
+      sql(s"CREATE TABLE t(name STRING DEFAULT 'test') $defaultUsing")
+      val descriptionDf = sql("DESCRIBE TABLE EXTENDED t name")
+      val defaultRows = descriptionDf.collect().filter(_.getString(0) == "default")
+      assert(defaultRows.length == 1, "Default value should appear only once")
+      assert(defaultRows(0).getString(1) == "'test'")
+    }
+  }
+
   test("DESCRIBE AS JSON partitions, clusters, buckets") {
     withNamespaceAndTable("ns", "table") { t =>
       val tableCreationStr =