This is an automated cherry-pick of pingcap#48815

Signed-off-by: ti-chi-bot <ti-community-prow-bot@tidb.io>

ddl/partition.go

@@ -711,12 +711,20 @@ func getPartitionIntervalFromTable(ctx sessionctx.Context, tbInfo *model.TableIn
 }
 
 // comparePartitionAstAndModel compares a generated *ast.PartitionOptions and a *model.PartitionInfo
-func comparePartitionAstAndModel(ctx sessionctx.Context, pAst *ast.PartitionOptions, pModel *model.PartitionInfo) error {
+func comparePartitionAstAndModel(ctx sessionctx.Context, pAst *ast.PartitionOptions, pModel *model.PartitionInfo, partCol *model.ColumnInfo) error {
 	a := pAst.Definitions
 	m := pModel.Definitions
 	if len(pAst.Definitions) != len(pModel.Definitions) {
 		return dbterror.ErrGeneralUnsupportedDDL.GenWithStackByArgs("INTERVAL partitioning: number of partitions generated != partition defined (%d != %d)", len(a), len(m))
 	}
+
+	evalFn := func(expr ast.ExprNode) (types.Datum, error) {
+		val, err := expression.EvalAstExpr(ctx, ast.NewValueExpr(expr, "", ""))
+		if err != nil || partCol == nil {
+			return val, err
+		}
+		return val.ConvertTo(ctx.GetSessionVars().StmtCtx.TypeCtx(), &partCol.FieldType)
+	}
 	for i := range pAst.Definitions {
 		// Allow options to differ! (like Placement Rules)
 		// Allow names to differ!
@@ -739,16 +747,19 @@ func comparePartitionAstAndModel(ctx sessionctx.Context, pAst *ast.PartitionOpti
 		if len(lessThan) > 1 && lessThan[:1] == "'" && lessThan[len(lessThan)-1:] == "'" {
 			lessThan = driver.UnwrapFromSingleQuotes(lessThan)
 		}
-		cmpExpr := &ast.BinaryOperationExpr{
-			Op: opcode.EQ,
-			L:  ast.NewValueExpr(lessThan, "", ""),
-			R:  generatedExpr,
+		lessThanVal, err := evalFn(ast.NewValueExpr(lessThan, "", ""))
+		if err != nil {
+			return err
 		}
-		cmp, err := expression.EvalAstExpr(ctx, cmpExpr)
+		generatedExprVal, err := evalFn(generatedExpr)
 		if err != nil {
 			return err
 		}
-		if cmp.GetInt64() != 1 {
+		cmp, err := lessThanVal.Compare(ctx.GetSessionVars().StmtCtx.TypeCtx(), &generatedExprVal, collate.GetBinaryCollator())
+		if err != nil {
+			return err
+		}
+		if cmp != 0 {
 			return dbterror.ErrGeneralUnsupportedDDL.GenWithStackByArgs(fmt.Sprintf("INTERVAL partitioning: LESS THAN for partition %s differs between generated and defined", m[i].Name.O))
 		}
 	}
@@ -923,7 +934,7 @@ func generatePartitionDefinitionsFromInterval(ctx sessionctx.Context, partOption
 		// Seems valid, so keep the defined so that the user defined names are kept etc.
 		partOptions.Definitions = definedPartDefs
 	} else if len(tbInfo.Partition.Definitions) > 0 {
-		err := comparePartitionAstAndModel(ctx, partOptions, tbInfo.Partition)
+		err := comparePartitionAstAndModel(ctx, partOptions, tbInfo.Partition, partCol)
 		if err != nil {
 			return err
 		}
@@ -997,6 +1008,12 @@ func GeneratePartDefsFromInterval(ctx sessionctx.Context, tp ast.AlterTableType,
 	if err != nil {
 		return err
 	}
+	if partCol != nil {
+		lastVal, err = lastVal.ConvertTo(ctx.GetSessionVars().StmtCtx.TypeCtx(), &partCol.FieldType)
+		if err != nil {
+			return err
+		}
+	}
 	var partDefs []*ast.PartitionDefinition
 	if len(partitionOptions.Definitions) != 0 {
 		partDefs = partitionOptions.Definitions
@@ -1040,7 +1057,17 @@ func GeneratePartDefsFromInterval(ctx sessionctx.Context, tp ast.AlterTableType,
 		if err != nil {
 			return err
 		}
+<<<<<<< HEAD:ddl/partition.go
 		cmp, err := currVal.Compare(ctx.GetSessionVars().StmtCtx, &lastVal, collate.GetBinaryCollator())
+=======
+		if partCol != nil {
+			currVal, err = currVal.ConvertTo(ctx.GetSessionVars().StmtCtx.TypeCtx(), &partCol.FieldType)
+			if err != nil {
+				return err
+			}
+		}
+		cmp, err := currVal.Compare(ctx.GetSessionVars().StmtCtx.TypeCtx(), &lastVal, collate.GetBinaryCollator())
+>>>>>>> 522cd038678 (ddl: fix issue of alter last partition failed when partition column is datetime (#48815)):pkg/ddl/partition.go
 		if err != nil {
 			return err
 		}

pkg/ddl/tests/partition/BUILD.bazel

@@ -0,0 +1,46 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_test")
+
+go_test(
+    name = "partition_test",
+    timeout = "short",
+    srcs = [
+        "db_partition_test.go",
+        "main_test.go",
+    ],
+    flaky = True,
+    shard_count = 48,
+    deps = [
+        "//pkg/config",
+        "//pkg/ddl",
+        "//pkg/ddl/testutil",
+        "//pkg/ddl/util/callback",
+        "//pkg/domain",
+        "//pkg/errno",
+        "//pkg/kv",
+        "//pkg/parser/ast",
+        "//pkg/parser/model",
+        "//pkg/parser/mysql",
+        "//pkg/parser/terror",
+        "//pkg/session",
+        "//pkg/sessionctx",
+        "//pkg/sessionctx/variable",
+        "//pkg/sessiontxn",
+        "//pkg/store/mockstore",
+        "//pkg/table",
+        "//pkg/table/tables",
+        "//pkg/tablecodec",
+        "//pkg/testkit",
+        "//pkg/testkit/external",
+        "//pkg/testkit/testsetup",
+        "//pkg/types",
+        "//pkg/util/codec",
+        "//pkg/util/dbterror",
+        "//pkg/util/logutil",
+        "@com_github_pingcap_errors//:errors",
+        "@com_github_pingcap_failpoint//:failpoint",
+        "@com_github_stretchr_testify//assert",
+        "@com_github_stretchr_testify//require",
+        "@org_uber_go_goleak//:goleak",
+        "@org_uber_go_zap//:zap",
+    ],
+)