diff --git a/ddl/backfilling.go b/ddl/backfilling.go
index 0736cbb58215f..7761003d78e23 100644
--- a/ddl/backfilling.go
+++ b/ddl/backfilling.go
@@ -471,6 +471,9 @@ func (dc *ddlCtx) handleRangeTasks(sessPool *sessionPool, t table.Table, workers
 	physicalTableID := reorgInfo.PhysicalTableID
 
 	var prefix kv.Key
+	if tbl, ok := t.(table.PartitionedTable); ok {
+		t = tbl.GetPartition(physicalTableID)
+	}
 	if reorgInfo.mergingTmpIdx {
 		prefix = t.IndexPrefix()
 	} else {
diff --git a/ddl/column.go b/ddl/column.go
index 6beba60a35d5c..10db5120e9351 100644
--- a/ddl/column.go
+++ b/ddl/column.go
@@ -1020,9 +1020,30 @@ func BuildElements(changingCol *model.ColumnInfo, changingIdxs []*model.IndexInf
 	return elements
 }
 
-func (w *worker) updatePhysicalTableRow(t table.PhysicalTable, reorgInfo *reorgInfo) error {
+func (w *worker) updatePhysicalTableRow(t table.Table, reorgInfo *reorgInfo) error {
 	logutil.BgLogger().Info("[ddl] start to update table row", zap.String("job", reorgInfo.Job.String()), zap.String("reorgInfo", reorgInfo.String()))
-	return w.writePhysicalTableRecord(w.sessPool, t, typeUpdateColumnWorker, reorgInfo)
+	if tbl, ok := t.(table.PartitionedTable); ok {
+		done := false
+		for !done {
+			p := tbl.GetPartition(reorgInfo.PhysicalTableID)
+			if p == nil {
+				return dbterror.ErrCancelledDDLJob.GenWithStack("Can not find partition id %d for table %d", reorgInfo.PhysicalTableID, t.Meta().ID)
+			}
+			err := w.writePhysicalTableRecord(w.sessPool, p, typeUpdateColumnWorker, reorgInfo)
+			if err != nil {
+				return err
+			}
+			done, err = w.updateReorgInfo(tbl, reorgInfo)
+			if err != nil {
+				return errors.Trace(err)
+			}
+		}
+		return nil
+	}
+	if tbl, ok := t.(table.PhysicalTable); ok {
+		return w.writePhysicalTableRecord(w.sessPool, tbl, typeUpdateColumnWorker, reorgInfo)
+	}
+	return dbterror.ErrCancelledDDLJob.GenWithStack("internal error for phys tbl id: %d tbl id: %d", reorgInfo.PhysicalTableID, t.Meta().ID)
 }
 
 // TestReorgGoroutineRunning is only used in test to indicate the reorg goroutine has been started.
@@ -1044,22 +1065,25 @@ func (w *worker) updateCurrentElement(t table.Table, reorgInfo *reorgInfo) error
 			}
 		}
 	})
-	// TODO: Support partition tables.
 	if bytes.Equal(reorgInfo.currElement.TypeKey, meta.ColumnElementKey) {
-		//nolint:forcetypeassert
-		err := w.updatePhysicalTableRow(t.(table.PhysicalTable), reorgInfo)
+		err := w.updatePhysicalTableRow(t, reorgInfo)
 		if err != nil {
 			return errors.Trace(err)
 		}
 	}
 
+	var physTbl table.PhysicalTable
+	if tbl, ok := t.(table.PartitionedTable); ok {
+		physTbl = tbl.GetPartition(reorgInfo.PhysicalTableID)
+	} else if tbl, ok := t.(table.PhysicalTable); ok {
+		physTbl = tbl
+	}
 	// Get the original start handle and end handle.
 	currentVer, err := getValidCurrentVersion(reorgInfo.d.store)
 	if err != nil {
 		return errors.Trace(err)
 	}
-	//nolint:forcetypeassert
-	originalStartHandle, originalEndHandle, err := getTableRange(reorgInfo.d.jobContext(reorgInfo.Job), reorgInfo.d, t.(table.PhysicalTable), currentVer.Ver, reorgInfo.Job.Priority)
+	originalStartHandle, originalEndHandle, err := getTableRange(reorgInfo.d.jobContext(reorgInfo.Job), reorgInfo.d, physTbl, currentVer.Ver, reorgInfo.Job.Priority)
 	if err != nil {
 		return errors.Trace(err)
 	}
diff --git a/ddl/db_partition_test.go b/ddl/db_partition_test.go
index ff75ba2f41b10..93ed264deb6e8 100644
--- a/ddl/db_partition_test.go
+++ b/ddl/db_partition_test.go
@@ -4528,3 +4528,131 @@ func TestPartitionTableWithAnsiQuotes(t *testing.T) {
 		` PARTITION "p4" VALUES LESS THAN ('\\''\t\n','\\''\t\n'),` + "\n" +
 		` PARTITION "pMax" VALUES LESS THAN (MAXVALUE,MAXVALUE))`))
 }
+func TestAlterModifyColumnOnPartitionedTable(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("create database AlterPartTable")
+	tk.MustExec("use AlterPartTable")
+	tk.MustExec(`create table t (a int unsigned PRIMARY KEY, b varchar(255), key (b))`)
+	tk.MustExec(`insert into t values (7, "07"), (8, "08"),(23,"23"),(34,"34💥"),(46,"46"),(57,"57")`)
+	tk.MustQuery(`show create table t`).Check(testkit.Rows(
+		"t CREATE TABLE `t` (\n" +
+			"  `a` int(10) unsigned NOT NULL,\n" +
+			"  `b` varchar(255) DEFAULT NULL,\n" +
+			"  PRIMARY KEY (`a`) /*T![clustered_index] CLUSTERED */,\n" +
+			"  KEY `b` (`b`)\n" +
+			") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin"))
+	// TODO: Why does it allow 💥 as a latin1 character?
+	tk.MustQuery(`select hex(b) from t where a = 34`).Check(testkit.Rows("3334F09F92A5"))
+	tk.MustExec(`alter table t modify b varchar(200) charset latin1`)
+	tk.MustQuery(`show create table t`).Check(testkit.Rows(
+		"t CREATE TABLE `t` (\n" +
+			"  `a` int(10) unsigned NOT NULL,\n" +
+			"  `b` varchar(200) CHARACTER SET latin1 COLLATE latin1_bin DEFAULT NULL,\n" +
+			"  PRIMARY KEY (`a`) /*T![clustered_index] CLUSTERED */,\n" +
+			"  KEY `b` (`b`)\n" +
+			") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin"))
+	tk.MustQuery(`select hex(b) from t where a = 34`).Check(testkit.Rows("3334F09F92A5"))
+	tk.MustQuery(`select * from t`).Sort().Check(testkit.Rows(""+
+		"23 23",
+		"34 34💥",
+		"46 46",
+		"57 57",
+		"7 07",
+		"8 08"))
+	tk.MustQuery(`select * from t order by b`).Check(testkit.Rows(""+
+		"7 07",
+		"8 08",
+		"23 23",
+		"34 34💥",
+		"46 46",
+		"57 57"))
+	tk.MustExec(`alter table t change b c varchar(200) charset utf8mb4`)
+	tk.MustExec(`drop table t`)
+	tk.MustExec(`create table t (a int unsigned PRIMARY KEY, b varchar(255), key (b)) partition by range (a) ` +
+		`(partition p0 values less than (10),` +
+		` partition p1 values less than (20),` +
+		` partition p2 values less than (30),` +
+		` partition pMax values less than (MAXVALUE))`)
+	tk.MustExec(`insert into t values (7, "07"), (8, "08"),(23,"23"),(34,"34💥"),(46,"46"),(57,"57")`)
+	tk.MustQuery(`select * from t`).Sort().Check(testkit.Rows(""+
+		"23 23",
+		"34 34💥",
+		"46 46",
+		"57 57",
+		"7 07",
+		"8 08"))
+	tk.MustQuery(`select * from t order by b`).Check(testkit.Rows(""+
+		"7 07",
+		"8 08",
+		"23 23",
+		"34 34💥",
+		"46 46",
+		"57 57"))
+	tk.MustQuery(`show create table t`).Check(testkit.Rows(
+		"t CREATE TABLE `t` (\n" +
+			"  `a` int(10) unsigned NOT NULL,\n" +
+			"  `b` varchar(255) DEFAULT NULL,\n" +
+			"  PRIMARY KEY (`a`) /*T![clustered_index] CLUSTERED */,\n" +
+			"  KEY `b` (`b`)\n" +
+			") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin\n" +
+			"PARTITION BY RANGE (`a`)\n" +
+			"(PARTITION `p0` VALUES LESS THAN (10),\n" +
+			" PARTITION `p1` VALUES LESS THAN (20),\n" +
+			" PARTITION `p2` VALUES LESS THAN (30),\n" +
+			" PARTITION `pMax` VALUES LESS THAN (MAXVALUE))"))
+	tk.MustExec(`alter table t modify b varchar(200) charset latin1`)
+	tk.MustQuery(`show create table t`).Check(testkit.Rows(
+		"t CREATE TABLE `t` (\n" +
+			"  `a` int(10) unsigned NOT NULL,\n" +
+			"  `b` varchar(200) CHARACTER SET latin1 COLLATE latin1_bin DEFAULT NULL,\n" +
+			"  PRIMARY KEY (`a`) /*T![clustered_index] CLUSTERED */,\n" +
+			"  KEY `b` (`b`)\n" +
+			") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin\n" +
+			"PARTITION BY RANGE (`a`)\n" +
+			"(PARTITION `p0` VALUES LESS THAN (10),\n" +
+			" PARTITION `p1` VALUES LESS THAN (20),\n" +
+			" PARTITION `p2` VALUES LESS THAN (30),\n" +
+			" PARTITION `pMax` VALUES LESS THAN (MAXVALUE))"))
+	tk.MustQuery(`select * from t`).Sort().Check(testkit.Rows(""+
+		"23 23",
+		"34 34💥",
+		"46 46",
+		"57 57",
+		"7 07",
+		"8 08"))
+	tk.MustQuery(`select * from t order by b`).Check(testkit.Rows(""+
+		"7 07",
+		"8 08",
+		"23 23",
+		"34 34💥",
+		"46 46",
+		"57 57"))
+	tk.MustExec(`alter table t change b c varchar(150) charset utf8mb4`)
+	tk.MustQuery(`show create table t`).Check(testkit.Rows(
+		"t CREATE TABLE `t` (\n" +
+			"  `a` int(10) unsigned NOT NULL,\n" +
+			"  `c` varchar(150) DEFAULT NULL,\n" +
+			"  PRIMARY KEY (`a`) /*T![clustered_index] CLUSTERED */,\n" +
+			"  KEY `b` (`c`)\n" +
+			") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin\n" +
+			"PARTITION BY RANGE (`a`)\n" +
+			"(PARTITION `p0` VALUES LESS THAN (10),\n" +
+			" PARTITION `p1` VALUES LESS THAN (20),\n" +
+			" PARTITION `p2` VALUES LESS THAN (30),\n" +
+			" PARTITION `pMax` VALUES LESS THAN (MAXVALUE))"))
+	tk.MustQuery(`select * from t`).Sort().Check(testkit.Rows(""+
+		"23 23",
+		"34 34💥",
+		"46 46",
+		"57 57",
+		"7 07",
+		"8 08"))
+	tk.MustQuery(`select * from t order by c`).Check(testkit.Rows(""+
+		"7 07",
+		"8 08",
+		"23 23",
+		"34 34💥",
+		"46 46",
+		"57 57"))
+}
diff --git a/ddl/ddl_api.go b/ddl/ddl_api.go
index 153567e2c9fe1..54f8243b6df8c 100644
--- a/ddl/ddl_api.go
+++ b/ddl/ddl_api.go
@@ -4543,9 +4543,6 @@ func GetModifiableColumnJob(
 		if err = isGeneratedRelatedColumn(t.Meta(), newCol.ColumnInfo, col.ColumnInfo); err != nil {
 			return nil, errors.Trace(err)
 		}
-		if t.Meta().Partition != nil {
-			return nil, dbterror.ErrUnsupportedModifyColumn.GenWithStackByArgs("table is partition table")
-		}
 	}
 
 	// We don't support modifying column from not_auto_increment to auto_increment.
diff --git a/ddl/failtest/fail_db_test.go b/ddl/failtest/fail_db_test.go
index e4d8ea7e58342..bde5e9b1b9569 100644
--- a/ddl/failtest/fail_db_test.go
+++ b/ddl/failtest/fail_db_test.go
@@ -493,8 +493,6 @@ func TestModifyColumn(t *testing.T) {
 	tk.MustExec("admin check table t")
 
 	// Test unsupported statements.
-	tk.MustExec("create table t1(a int) partition by hash (a) partitions 2")
-	tk.MustGetErrMsg("alter table t1 modify column a mediumint", "[ddl:8200]Unsupported modify column: table is partition table")
 	tk.MustExec("create table t2(id int, a int, b int generated always as (abs(a)) virtual, c int generated always as (a+1) stored)")
 	tk.MustGetErrMsg("alter table t2 modify column b mediumint", "[ddl:8200]Unsupported modify column: newCol IsGenerated false, oldCol IsGenerated true")
 	tk.MustGetErrMsg("alter table t2 modify column c mediumint", "[ddl:8200]Unsupported modify column: newCol IsGenerated false, oldCol IsGenerated true")
@@ -531,7 +529,7 @@ func TestModifyColumn(t *testing.T) {
 	tk.MustExec("insert into t5 values (1,1),(2,2),(3,3),(4,4),(5,5);")
 	tk.MustExec("alter table t5 modify a int not null;")
 
-	tk.MustExec("drop table t, t1, t2, t3, t4, t5")
+	tk.MustExec("drop table t, t2, t3, t4, t5")
 }
 
 func TestPartitionAddPanic(t *testing.T) {
diff --git a/expression/expression.go b/expression/expression.go
index e8f38910c1264..e4b8ae764a2bd 100644
--- a/expression/expression.go
+++ b/expression/expression.go
@@ -818,6 +818,10 @@ func EvaluateExprWithNull(ctx sessionctx.Context, schema *Schema, expr Expressio
 	if MaybeOverOptimized4PlanCache(ctx, []Expression{expr}) {
 		return expr
 	}
+	if ctx.GetSessionVars().StmtCtx.InNullRejectCheck {
+		expr, _ = evaluateExprWithNullInNullRejectCheck(ctx, schema, expr)
+		return expr
+	}
 	return evaluateExprWithNull(ctx, schema, expr)
 }
 
@@ -842,6 +846,70 @@ func evaluateExprWithNull(ctx sessionctx.Context, schema *Schema, expr Expressio
 	return expr
 }
 
+// evaluateExprWithNullInNullRejectCheck sets columns in schema as null and calculate the final result of the scalar function.
+// If the Expression is a non-constant value, it means the result is unknown.
+// The returned bool values indicates whether the value is influenced by the Null Constant transformed from schema column
+// when the value is Null Constant.
+func evaluateExprWithNullInNullRejectCheck(ctx sessionctx.Context, schema *Schema, expr Expression) (Expression, bool) {
+	switch x := expr.(type) {
+	case *ScalarFunction:
+		args := make([]Expression, len(x.GetArgs()))
+		nullFromSets := make([]bool, len(x.GetArgs()))
+		for i, arg := range x.GetArgs() {
+			args[i], nullFromSets[i] = evaluateExprWithNullInNullRejectCheck(ctx, schema, arg)
+		}
+
+		// allNullFromSet indicates whether all arguments are Null Constant and the Null Constant is affected by the column of the schema.
+		allNullFromSet := true
+		for i := range args {
+			if cons, ok := args[i].(*Constant); ok && cons.Value.IsNull() && !nullFromSets[i] {
+				allNullFromSet = false
+				break
+			}
+		}
+
+		// allArgsNullFromSet indicates whether all Null Constant are affected by the column of the schema
+		allArgsNullFromSet := true
+		for i := range args {
+			if cons, ok := args[i].(*Constant); ok && cons.Value.IsNull() && nullFromSets[i] {
+				continue
+			}
+			allArgsNullFromSet = false
+		}
+
+		// If all the args are Null Constant and affected by the column schema, then we should keep it.
+		// Otherwise, we shouldn't let Null Constant which affected by the column schema participate in computing in `And` and `OR`
+		// due to the result of `AND` and `OR are uncertain if one of the arguments is NULL.
+		if !allArgsNullFromSet {
+			for i := range args {
+				if cons, ok := args[i].(*Constant); ok && cons.Value.IsNull() && nullFromSets[i] {
+					if x.FuncName.L == ast.LogicAnd {
+						args[i] = NewOne()
+					}
+					if x.FuncName.L == ast.LogicOr {
+						args[i] = NewZero()
+					}
+				}
+			}
+		}
+		c := NewFunctionInternal(ctx, x.FuncName.L, x.RetType.Clone(), args...)
+		cons, ok := c.(*Constant)
+		// If the return expr is Null Constant, and all the Null Constant arguments are affected by column schema,
+		// then we think the result Null Constant is also affected by the column schema
+		return c, ok && cons.Value.IsNull() && allNullFromSet
+	case *Column:
+		if !schema.Contains(x) {
+			return x, false
+		}
+		return &Constant{Value: types.Datum{}, RetType: types.NewFieldType(mysql.TypeNull)}, true
+	case *Constant:
+		if x.DeferredExpr != nil {
+			return FoldConstant(x), false
+		}
+	}
+	return expr, false
+}
+
 // TableInfo2SchemaAndNames converts the TableInfo to the schema and name slice.
 func TableInfo2SchemaAndNames(ctx sessionctx.Context, dbName model.CIStr, tbl *model.TableInfo) (*Schema, []*types.FieldName, error) {
 	cols, names, err := ColumnInfos2ColumnsAndNames(ctx, dbName, tbl.Name, tbl.Cols(), tbl)
diff --git a/planner/core/plan_test.go b/planner/core/plan_test.go
index 242d868a8c571..ebbb9c7373401 100644
--- a/planner/core/plan_test.go
+++ b/planner/core/plan_test.go
@@ -1076,3 +1076,19 @@ func TestNullEQConditionPlan(t *testing.T) {
 			{"Point_Get_5", "root", "handle:0"},
 		})
 }
+
+// https://github.com/pingcap/tidb/issues/38304
+func TestOuterJoinOnNull(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("CREATE TABLE t0(c0 BLOB(5), c1 BLOB(5));")
+	tk.MustExec("CREATE TABLE t1 (c0 BOOL);")
+	tk.MustExec("INSERT INTO t1 VALUES(false);")
+	tk.MustExec("INSERT INTO t0(c0, c1) VALUES ('>', true);")
+	tk.MustQuery("SELECT * FROM t0 LEFT OUTER JOIN t1 ON NULL; ").Check(testkit.Rows("> 1 <nil>"))
+	tk.MustQuery("SELECT NOT '2' =(t1.c0 AND t0.c1 IS NULL) FROM t0 LEFT OUTER JOIN t1 ON NULL; ").Check(testkit.Rows("1"))
+	tk.MustQuery("SELECT * FROM t0 LEFT JOIN t1 ON NULL WHERE NOT '2' =(t1.c0 AND t0.c1 IS NULL); ").Check(testkit.Rows("> 1 <nil>"))
+	tk.MustQuery("SELECT * FROM t0 LEFT JOIN t1 ON NULL WHERE t1.c0 or true; ").Check(testkit.Rows("> 1 <nil>"))
+	tk.MustQuery("SELECT * FROM t0 LEFT JOIN t1 ON NULL WHERE not(t1.c0 and false); ").Check(testkit.Rows("> 1 <nil>"))
+}
diff --git a/planner/core/rule_predicate_push_down.go b/planner/core/rule_predicate_push_down.go
index 96d62942f2346..bebed1cab141a 100644
--- a/planner/core/rule_predicate_push_down.go
+++ b/planner/core/rule_predicate_push_down.go
@@ -440,16 +440,20 @@ func isNullRejected(ctx sessionctx.Context, schema *expression.Schema, expr expr
 	}
 	sc := ctx.GetSessionVars().StmtCtx
 	sc.InNullRejectCheck = true
-	result := expression.EvaluateExprWithNull(ctx, schema, expr)
-	sc.InNullRejectCheck = false
-	x, ok := result.(*expression.Constant)
-	if !ok {
-		return false
-	}
-	if x.Value.IsNull() {
-		return true
-	} else if isTrue, err := x.Value.ToBool(sc); err == nil && isTrue == 0 {
-		return true
+	defer func() {
+		sc.InNullRejectCheck = false
+	}()
+	for _, cond := range expression.SplitCNFItems(expr) {
+		result := expression.EvaluateExprWithNull(ctx, schema, cond)
+		x, ok := result.(*expression.Constant)
+		if !ok {
+			continue
+		}
+		if x.Value.IsNull() {
+			return true
+		} else if isTrue, err := x.Value.ToBool(sc); err == nil && isTrue == 0 {
+			return true
+		}
 	}
 	return false
 }
diff --git a/store/mockstore/unistore/cophandler/cop_handler.go b/store/mockstore/unistore/cophandler/cop_handler.go
index 5f375f2bfdc30..2b32c168329bd 100644
--- a/store/mockstore/unistore/cophandler/cop_handler.go
+++ b/store/mockstore/unistore/cophandler/cop_handler.go
@@ -401,7 +401,7 @@ func newRowDecoder(columnInfos []*tipb.ColumnInfo, fieldTps []*types.FieldType,
 		if primaryCols != nil {
 			pkCols = primaryCols
 		} else {
-			pkCols = []int64{0}
+			pkCols = []int64{-1}
 		}
 	}
 	def := func(i int, chk *chunk.Chunk) error {