Merge pull request #7740 from planetscale/nullable-timestamp

Nullable Timestamp Column Fix

go/vt/sqlparser/ast.go

@@ -1364,7 +1364,14 @@ type ColumnType struct {
 
 // ColumnTypeOptions are generic field options for a column type
 type ColumnTypeOptions struct {
-	NotNull       bool
+	/* We need Null to be *bool to distinguish 3 cases -
+	1. When Not Null is specified (Null = false)
+	2. When Null is specified (Null = true)
+	3. When nothing is specified (Null = nil)
+	The complexity arises from the fact that we do not know whether the column will be nullable or not if nothing is specified.
+	Therefore we do not know whether the column is nullable or not in case 3.
+	*/
+	Null          *bool
 	Autoincrement bool
 	Default       Expr
 	OnUpdate      Expr

go/vt/sqlparser/ast_format.go

@@ -456,8 +456,12 @@ func (ct *ColumnType) Format(buf *TrackedBuffer) {
 	if ct.Collate != "" {
 		buf.astPrintf(ct, " %s %s", keywordStrings[COLLATE], ct.Collate)
 	}
-	if ct.Options.NotNull {
-		buf.astPrintf(ct, " %s %s", keywordStrings[NOT], keywordStrings[NULL])
+	if ct.Options.Null != nil {
+		if *ct.Options.Null {
+			buf.astPrintf(ct, " %s", keywordStrings[NULL])
+		} else {
+			buf.astPrintf(ct, " %s %s", keywordStrings[NOT], keywordStrings[NULL])
+		}
 	}
 	if ct.Options.Default != nil {
 		buf.astPrintf(ct, " %s %v", keywordStrings[DEFAULT], ct.Options.Default)

go/vt/sqlparser/parse_test.go

@@ -1156,6 +1156,12 @@ var (
 	}, {
 		input:  "CREATE TABLE aipk (id INT AUTO_INCREMENT PRIMARY KEY)",
 		output: "create table aipk (\n\tid INT auto_increment primary key\n)",
+	}, {
+		// This test case is added because MySQL supports this behaviour.
+		// It allows the user to specify null and not null multiple times.
+		// The last value specified is used.
+		input:  "create table foo (f timestamp null not null , g timestamp not null null)",
+		output: "create table foo (\n\tf timestamp not null,\n\tg timestamp null\n)",
 	}, {
 		input: "alter vschema create vindex hash_vdx using hash",
 	}, {
@@ -2569,6 +2575,14 @@ func TestCreateTable(t *testing.T) {
 			"	col_multipolygon2 multipolygon not null\n" +
 			")",
 
+		// test null columns
+		"create table foo (\n" +
+			"	id int primary key,\n" +
+			"	a varchar(255) null,\n" +
+			"	b varchar(255) null default 'foo',\n" +
+			"	c timestamp null default current_timestamp()\n" +
+			")",
+
 		// test defining indexes separately
 		"create table t (\n" +
 			"	id int auto_increment,\n" +