[SPARK-59573][SQL] Fix multi-value UNPIVOT with mixed types

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

@@ -2378,7 +2378,15 @@ class AstBuilder extends DataTypeAstBuilder
 
     // exclude null values by default
     val filtered = if (ctx.nullOperator == null || ctx.nullOperator.EXCLUDE() != null) {
-      Filter(IsNotNull(Coalesce(valueColumnNames.map(UnresolvedAttribute(_)))), unpivot)
+      val valueColumns = valueColumnNames.map(UnresolvedAttribute(_))
+      val condition = if (valueColumns.length == 1) {
+        // Keep the single-value plan stable; unary Coalesce does not require type coercion.
+        IsNotNull(Coalesce(valueColumns))
+      } else {
+        // Multi-value columns can have unrelated types, so test each for null independently.
+        valueColumns.map(IsNotNull).reduceLeft(Or)
+      }
+      Filter(condition, unpivot)
     } else {
       unpivot
     }

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

@@ -62,7 +62,7 @@ class IdentifierClauseParserSuite extends AnalysisTest {
         "col",
         Seq("v1", "v2"),
         table("unpivot_test"))
-        .where(coalesce($"v1", $"v2").isNotNull)
+        .where($"v1".isNotNull || $"v2".isNotNull)
         .select(star())
     )
   }

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

@@ -81,7 +81,7 @@ class UnpivotParserSuite extends AnalysisTest {
         "col",
         Seq("val1", "val2"),
         table("t"))
-        .where(coalesce($"val1", $"val2").isNotNull)
+        .where($"val1".isNotNull || $"val2".isNotNull)
         .select(star())
     )
   }
@@ -101,13 +101,23 @@ class UnpivotParserSuite extends AnalysisTest {
             "col",
             Seq("val1", "val2"),
             table("t"))
-            .where(coalesce($"val1", $"val2").isNotNull)
+            .where($"val1".isNotNull || $"val2".isNotNull)
             .select(star())
         )
       }
     }
   }
 
+  test("unpivot - multiple values with different types") {
+    assertAnalysisSuccess(parsePlan(
+      """SELECT * FROM VALUES
+        |  (DATE '2026-01-01', 1, DATE '2026-01-02', 2)
+        |  AS t(date1, int1, date2, int2)
+        |UNPIVOT EXCLUDE NULLS (
+        |  (date_value, int_value) FOR kind IN ((date1, int1), (date2, int2))
+        |)""".stripMargin))
+  }
+
   test("unpivot - multiple values with inner alias") {
     Seq(
       "SELECT * FROM t UNPIVOT ((val1, val2) FOR col in ((a A, b), (c, d)))",

sql/core/src/test/resources/sql-tests/analyzer-results/identifier-clause.sql.out

@@ -2737,7 +2737,7 @@ SELECT * FROM unpivot_test UNPIVOT ((v1, v2) FOR col IN ((a, b) AS IDENTIFIER('c
 -- !query analysis
 Sort [id#x ASC NULLS FIRST, col#x ASC NULLS FIRST, v1#x ASC NULLS FIRST, v2#x ASC NULLS FIRST], true
 +- Project [id#x, col#x, v1#x, v2#x]
-   +- Filter isnotnull(coalesce(v1#x, v2#x))
+   +- Filter (isnotnull(v1#x) OR isnotnull(v2#x))
       +- Expand [[id#x, cols_ab, a#x, b#x], [id#x, cols_bc, b#x, c#x]], [id#x, col#x, v1#x, v2#x]
          +- SubqueryAlias spark_catalog.identifier_clause_test_schema.unpivot_test
             +- Relation spark_catalog.identifier_clause_test_schema.unpivot_test[id#x,a#x,b#x,c#x] csv

sql/core/src/test/resources/sql-tests/analyzer-results/unpivot.sql.out

@@ -86,7 +86,7 @@ UNPIVOT (
 )
 -- !query analysis
 Project [course#x, year#x, earnings#x, sales#x]
-+- Filter isnotnull(coalesce(earnings#x, sales#x))
++- Filter (isnotnull(earnings#x) OR isnotnull(sales#x))
    +- Expand [[course#x, earnings2012_sales2012, earnings2012#x, sales2012#x], [course#x, earnings2013_sales2013, earnings2013#x, sales2013#x], [course#x, earnings2014_sales2014, earnings2014#x, sales2014#x]], [course#x, year#x, earnings#x, sales#x]
       +- SubqueryAlias courseearningsandsales
          +- View (`courseEarningsAndSales`, [course#x, earnings2012#x, sales2012#x, earnings2013#x, sales2013#x, earnings2014#x, sales2014#x])
@@ -119,11 +119,70 @@ UNPIVOT (
 )
 -- !query analysis
 Project [course#x, year#x, earnings#x, sales#x]
-+- Filter isnotnull(coalesce(earnings#x, sales#x))
++- Filter (isnotnull(earnings#x) OR isnotnull(sales#x))
    +- Expand [[course#x, 2012, earnings2012#x, sales2012#x], [course#x, 2013, earnings2013#x, sales2013#x], [course#x, 2014, earnings2014#x, sales2014#x]], [course#x, year#x, earnings#x, sales#x]
       +- SubqueryAlias courseearningsandsales
          +- View (`courseEarningsAndSales`, [course#x, earnings2012#x, sales2012#x, earnings2013#x, sales2013#x, earnings2014#x, sales2014#x])
             +- Project [cast(course#x as string) AS course#x, cast(earnings2012#x as int) AS earnings2012#x, cast(sales2012#x as int) AS sales2012#x, cast(earnings2013#x as int) AS earnings2013#x, cast(sales2013#x as int) AS sales2013#x, cast(earnings2014#x as int) AS earnings2014#x, cast(sales2014#x as int) AS sales2014#x]
                +- Project [course#x, earnings2012#x, sales2012#x, earnings2013#x, sales2013#x, earnings2014#x, sales2014#x]
                   +- SubqueryAlias courseEarningsAndSales
                      +- LocalRelation [course#x, earnings2012#x, sales2012#x, earnings2013#x, sales2013#x, earnings2014#x, sales2014#x]
+
+
+-- !query
+create temporary view mixedTypeValues as select
+  1 as id,
+  cast('2026-01-01' as date) as date1, cast(null as int) as int1,
+  cast(null as date) as date2, 2 as int2,
+  cast(null as date) as date3, cast(null as int) as int3
+-- !query analysis
+CreateViewCommand `mixedTypeValues`, select
+  1 as id,
+  cast('2026-01-01' as date) as date1, cast(null as int) as int1,
+  cast(null as date) as date2, 2 as int2,
+  cast(null as date) as date3, cast(null as int) as int3, false, false, LocalTempView, UNSUPPORTED, true
+   +- Project [1 AS id#x, cast(2026-01-01 as date) AS date1#x, cast(null as int) AS int1#x, cast(null as date) AS date2#x, 2 AS int2#x, cast(null as date) AS date3#x, cast(null as int) AS int3#x]
+      +- OneRowRelation
+
+
+-- !query
+SELECT * FROM mixedTypeValues
+UNPIVOT EXCLUDE NULLS (
+  (date_value, int_value) FOR kind IN (
+    (date1, int1) as date_only,
+    (date2, int2) as int_only,
+    (date3, int3) as all_null
+  )
+)
+ORDER BY kind
+-- !query analysis
+Sort [kind#x ASC NULLS FIRST], true
++- Project [id#x, kind#x, date_value#x, int_value#x]
+   +- Filter (isnotnull(date_value#x) OR isnotnull(int_value#x))
+      +- Expand [[id#x, date_only, date1#x, int1#x], [id#x, int_only, date2#x, int2#x], [id#x, all_null, date3#x, int3#x]], [id#x, kind#x, date_value#x, int_value#x]
+         +- SubqueryAlias mixedtypevalues
+            +- View (`mixedTypeValues`, [id#x, date1#x, int1#x, date2#x, int2#x, date3#x, int3#x])
+               +- Project [cast(id#x as int) AS id#x, cast(date1#x as date) AS date1#x, cast(int1#x as int) AS int1#x, cast(date2#x as date) AS date2#x, cast(int2#x as int) AS int2#x, cast(date3#x as date) AS date3#x, cast(int3#x as int) AS int3#x]
+                  +- Project [1 AS id#x, cast(2026-01-01 as date) AS date1#x, cast(null as int) AS int1#x, cast(null as date) AS date2#x, 2 AS int2#x, cast(null as date) AS date3#x, cast(null as int) AS int3#x]
+                     +- OneRowRelation
+
+
+-- !query
+SELECT * FROM mixedTypeValues
+UNPIVOT INCLUDE NULLS (
+  (date_value, int_value) FOR kind IN (
+    (date1, int1) as date_only,
+    (date2, int2) as int_only,
+    (date3, int3) as all_null
+  )
+)
+ORDER BY kind
+-- !query analysis
+Sort [kind#x ASC NULLS FIRST], true
++- Project [id#x, kind#x, date_value#x, int_value#x]
+   +- Expand [[id#x, date_only, date1#x, int1#x], [id#x, int_only, date2#x, int2#x], [id#x, all_null, date3#x, int3#x]], [id#x, kind#x, date_value#x, int_value#x]
+      +- SubqueryAlias mixedtypevalues
+         +- View (`mixedTypeValues`, [id#x, date1#x, int1#x, date2#x, int2#x, date3#x, int3#x])
+            +- Project [cast(id#x as int) AS id#x, cast(date1#x as date) AS date1#x, cast(int1#x as int) AS int1#x, cast(date2#x as date) AS date2#x, cast(int2#x as int) AS int2#x, cast(date3#x as date) AS date3#x, cast(int3#x as int) AS int3#x]
+               +- Project [1 AS id#x, cast(2026-01-01 as date) AS date1#x, cast(null as int) AS int1#x, cast(null as date) AS date2#x, 2 AS int2#x, cast(null as date) AS date3#x, cast(null as int) AS int3#x]
+                  +- OneRowRelation

sql/core/src/test/resources/sql-tests/inputs/unpivot.sql

@@ -42,3 +42,32 @@ SELECT * FROM courseEarningsAndSales
 UNPIVOT (
   (earnings, sales) FOR year IN ((earnings2012, sales2012) as `2012`, (earnings2013, sales2013) as `2013`, (earnings2014, sales2014) as `2014`)
 );
+
+
+create temporary view mixedTypeValues as select
+  1 as id,
+  cast('2026-01-01' as date) as date1, cast(null as int) as int1,
+  cast(null as date) as date2, 2 as int2,
+  cast(null as date) as date3, cast(null as int) as int3;
+
+-- EXCLUDE NULLS keeps partially-null tuples and removes all-null tuples across different types
+SELECT * FROM mixedTypeValues
+UNPIVOT EXCLUDE NULLS (
+  (date_value, int_value) FOR kind IN (
+    (date1, int1) as date_only,
+    (date2, int2) as int_only,
+    (date3, int3) as all_null
+  )
+)
+ORDER BY kind;
+
+-- INCLUDE NULLS retains the all-null tuple that EXCLUDE NULLS drops above
+SELECT * FROM mixedTypeValues
+UNPIVOT INCLUDE NULLS (
+  (date_value, int_value) FOR kind IN (
+    (date1, int1) as date_only,
+    (date2, int2) as int_only,
+    (date3, int3) as all_null
+  )
+)
+ORDER BY kind;

sql/core/src/test/resources/sql-tests/results/unpivot.sql.out

@@ -111,3 +111,50 @@ Java	2013	30000	2
 dotNET	2012	15000	NULL
 dotNET	2013	48000	1
 dotNET	2014	22500	1
+
+
+-- !query
+create temporary view mixedTypeValues as select
+  1 as id,
+  cast('2026-01-01' as date) as date1, cast(null as int) as int1,
+  cast(null as date) as date2, 2 as int2,
+  cast(null as date) as date3, cast(null as int) as int3
+-- !query schema
+struct<>
+-- !query output
+
+
+
+-- !query
+SELECT * FROM mixedTypeValues
+UNPIVOT EXCLUDE NULLS (
+  (date_value, int_value) FOR kind IN (
+    (date1, int1) as date_only,
+    (date2, int2) as int_only,
+    (date3, int3) as all_null
+  )
+)
+ORDER BY kind
+-- !query schema
+struct<id:int,kind:string,date_value:date,int_value:int>
+-- !query output
+1	date_only	2026-01-01	NULL
+1	int_only	NULL	2
+
+
+-- !query
+SELECT * FROM mixedTypeValues
+UNPIVOT INCLUDE NULLS (
+  (date_value, int_value) FOR kind IN (
+    (date1, int1) as date_only,
+    (date2, int2) as int_only,
+    (date3, int3) as all_null
+  )
+)
+ORDER BY kind
+-- !query schema
+struct<id:int,kind:string,date_value:date,int_value:int>
+-- !query output
+1	all_null	NULL	NULL
+1	date_only	2026-01-01	NULL
+1	int_only	NULL	2