update and add more tests

Author: angelamayxie

enginetest/queries/function_queries.go

@@ -2105,4 +2105,12 @@ var FunctionQueryTests = []QueryTest{
 		Query:    "select date('0000-01-01')",
 		Expected: []sql.Row{{"0000-01-01"}},
 	},
+	{
+		Query:    "select date('0000-00-00')",
+		Expected: []sql.Row{{"0000-00-00"}},
+	},
+	{
+		Query:    "select date(0)",
+		Expected: []sql.Row{{"0000-00-00"}},
+	},
 }

enginetest/queries/insert_queries.go

@@ -2349,6 +2349,25 @@ var InsertScripts = []ScriptTest{
 			},
 		},
 	},
+	{
+		Name: "inserting zero date",
+		SetUpScript: []string{
+			"create table t(d date)",
+			"insert into t values ('0000-00-00')",
+			"create table t2(d datetime)",
+			"insert into t2 values ('0000-00-00')",
+		},
+		Assertions: []ScriptTestAssertion{
+			{
+				Query:    "select * from t",
+				Expected: []sql.Row{{types.ZeroTime}},
+			},
+			{
+				Query:    "select * from t2",
+				Expected: []sql.Row{{types.ZeroTime}},
+			},
+		},
+	},
 }
 
 var InsertDuplicateKeyKeyless = []ScriptTest{

sql/expression/function/time.go

@@ -1300,7 +1300,14 @@ func (d *Date) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
 			return nil
 		}
 
-		return v.(time.Time).Format("2006-01-02")
+		date, ok := v.(time.Time)
+		if !ok {
+			return nil
+		}
+		if date.Equal(types.ZeroTime) {
+			return types.ZeroDateStr
+		}
+		return date.Format("2006-01-02")
 	})
 }
 

sql/rowexec/update_test.go

@@ -15,11 +15,9 @@
 package rowexec
 
 import (
-	"testing"
-	"time"
-
 	"github.com/dolthub/vitess/go/sqltypes"
 	"github.com/stretchr/testify/require"
+	"testing"
 
 	"github.com/dolthub/go-mysql-server/memory"
 	"github.com/dolthub/go-mysql-server/sql"
@@ -55,7 +53,7 @@ func TestUpdateIgnoreConversions(t *testing.T) {
 			colType:   types.Datetime,
 			value:     "dadasd",
 			valueType: types.Text,
-			expected:  time.Unix(-62167219200, 0).UTC(),
+			expected:  types.ZeroTime,
 		},
 		{
 			name:      "inserting a negative into an unsigned int results in 0",