parser: support sql_mode REAL_AS_FLOAT

mysql/const.go

@@ -427,6 +427,11 @@ func (m SQLMode) HasStrictMode() bool {
 	return m&ModeStrictTransTables == ModeStrictTransTables || m&ModeStrictAllTables == ModeStrictAllTables
 }
 
+// HasRealAsFloatMode detects if 'REAL_AS_FLOAT' mode is set in SQLMode
+func (m SQLMode) HasRealAsFloatMode() bool {
+	return m&ModeRealAsFloat == ModeRealAsFloat
+}
+
 // consts for sql modes.
 const (
 	ModeNone        SQLMode = 0

mysql/const_test.go

@@ -11,10 +11,18 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package mysql
+package mysql_test
 
 import (
+	"flag"
 	. "github.com/pingcap/check"
+	"github.com/pingcap/tidb"
+	"github.com/pingcap/tidb/kv"
+	"github.com/pingcap/tidb/mysql"
+	"github.com/pingcap/tidb/parser"
+	"github.com/pingcap/tidb/store/tikv"
+	"github.com/pingcap/tidb/store/tikv/mock-tikv"
+	"github.com/pingcap/tidb/util/testkit"
 	"github.com/pingcap/tidb/util/testleak"
 	"testing"
 )
@@ -27,6 +35,37 @@ func TestT(t *testing.T) {
 var _ = Suite(&testMySQLConstSuite{})
 
 type testMySQLConstSuite struct {
+	cluster   *mocktikv.Cluster
+	mvccStore *mocktikv.MvccStore
+	store     kv.Storage
+	*parser.Parser
+}
+
+var mockTikv = flag.Bool("mockTikv", true, "use mock tikv store in executor test")
+
+func (s *testMySQLConstSuite) SetUpSuite(c *C) {
+	s.Parser = parser.New()
+	flag.Lookup("mockTikv")
+	useMockTikv := *mockTikv
+	if useMockTikv {
+		s.cluster = mocktikv.NewCluster()
+		mocktikv.BootstrapWithSingleStore(s.cluster)
+		s.mvccStore = mocktikv.NewMvccStore()
+		store, err := tikv.NewMockTikvStore(
+			tikv.WithCluster(s.cluster),
+			tikv.WithMVCCStore(s.mvccStore),
+		)
+		c.Assert(err, IsNil)
+		s.store = store
+		tidb.SetSchemaLease(0)
+		tidb.SetStatsLease(0)
+	} else {
+		store, err := tidb.NewStore("memory://test/test")
+		c.Assert(err, IsNil)
+		s.store = store
+	}
+	_, err := tidb.BootstrapSession(s.store)
+	c.Assert(err, IsNil)
 }
 
 func (s *testMySQLConstSuite) TestGetSQLMode(c *C) {
@@ -44,7 +83,7 @@ func (s *testMySQLConstSuite) TestGetSQLMode(c *C) {
 	}
 
 	for _, t := range positiveCases {
-		_, err := GetSQLMode(FormatSQLModeStr(t.arg))
+		_, err := mysql.GetSQLMode(mysql.FormatSQLModeStr(t.arg))
 		c.Assert(err, IsNil)
 	}
 
@@ -58,7 +97,7 @@ func (s *testMySQLConstSuite) TestGetSQLMode(c *C) {
 	}
 
 	for _, t := range negativeCases {
-		_, err := GetSQLMode(FormatSQLModeStr(t.arg))
+		_, err := mysql.GetSQLMode(mysql.FormatSQLModeStr(t.arg))
 		c.Assert(err, NotNil)
 	}
 }
@@ -84,9 +123,28 @@ func (s *testMySQLConstSuite) TestSQLMode(c *C) {
 	}
 
 	for _, t := range tests {
-		sqlMode, _ := GetSQLMode(t.arg)
+		sqlMode, _ := mysql.GetSQLMode(t.arg)
 		c.Assert(sqlMode.HasNoZeroDateMode(), Equals, t.hasNoZeroDateMode)
 		c.Assert(sqlMode.HasNoZeroInDateMode(), Equals, t.hasNoZeroInDateMode)
 		c.Assert(sqlMode.HasErrorForDivisionByZeroMode(), Equals, t.hasErrorForDivisionByZeroMode)
 	}
 }
+
+func (s *testMySQLConstSuite) TestRealAsFloatMode(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t;")
+	tk.MustExec("create table t (a real);")
+	result := tk.MustQuery("desc t")
+	c.Check(result.Rows(), HasLen, 1)
+	row := result.Rows()[0]
+	c.Assert(row[1], Equals, "double")
+
+	tk.MustExec("drop table if exists t;")
+	tk.MustExec("set sql_mode='REAL_AS_FLOAT'")
+	tk.MustExec("create table t (a real)")
+	result = tk.MustQuery("desc t")
+	c.Check(result.Rows(), HasLen, 1)
+	row = result.Rows()[0]
+	c.Assert(row[1], Equals, "float")
+}

parser/lexer.go

@@ -176,6 +176,11 @@ func (s *Scanner) SetSQLMode(mode mysql.SQLMode) {
 	s.sqlMode = mode
 }
 
+// GetSQLMode return the SQL mode of scanner.
+func (s *Scanner) GetSQLMode() mysql.SQLMode {
+	return s.sqlMode
+}
+
 // NewScanner returns a new scanner object.
 func NewScanner(s string) *Scanner {
 	return &Scanner{r: reader{s: s}}

parser/parser.y

@@ -5258,7 +5258,11 @@ FloatingPointType:
 	}
 |	"REAL"
 	{
-		$$ = mysql.TypeDouble
+	    if parser.lexer.GetSQLMode().HasRealAsFloatMode() {
+		    $$ = mysql.TypeFloat
+	    } else {
+		    $$ = mysql.TypeDouble
+	    }
 	}
 |	"DOUBLE"
 	{