Bug fix: record last_insert_id when 0 is specified for the auto_increment column value

enginetest/queries/insert_queries.go

@@ -556,8 +556,10 @@ var InsertQueries = []WriteQueryTest{
 		Dialect: "mysql",
 	},
 	{
+		// When 0 is specified for the auto_increment column (and SQL_MODE does not include
+		// NO_AUTO_VALUE_ON_ZERO), then an auto_increment value will be filled in.
 		WriteQuery:          "INSERT INTO auto_increment_tbl values (0, 44)",
-		ExpectedWriteResult: []sql.Row{{types.OkResult{RowsAffected: 1, InsertID: 0}}},
+		ExpectedWriteResult: []sql.Row{{types.OkResult{RowsAffected: 1, InsertID: 4}}},
 		SelectQuery:         "SELECT * FROM auto_increment_tbl ORDER BY pk",
 		ExpectedSelect: []sql.Row{
 			{1, 11},

sql/analyzer/inserts.go

@@ -184,7 +184,10 @@ func wrapRowSource(ctx *sql.Context, insertSource sql.Node, destTbl sql.Table, s
 							break
 						}
 						if lit, isLit := expr.(*expression.Literal); isLit {
-							if types.Null.Equals(lit.Type()) {
+							// If a literal NULL or if 0 is specified and the NO_AUTO_VALUE_ON_ZERO SQL mode is
+							// not active, then MySQL will fill in an auto_increment value.
+							if types.Null.Equals(lit.Type()) ||
+								(!sql.LoadSqlMode(ctx).ModeEnabled(sql.NoAutoValueOnZero) && isZero(lit)) {
 								firstGeneratedAutoIncRowIdx = ii
 								break
 							}
@@ -222,6 +225,21 @@ func wrapRowSource(ctx *sql.Context, insertSource sql.Node, destTbl sql.Table, s
 	return plan.NewProject(projExprs, insertSource), firstGeneratedAutoIncRowIdx, nil
 }
 
+// isZero returns true if the specified literal value |lit| has a value equal to 0.
+func isZero(lit *expression.Literal) bool {
+	if !types.IsNumber(lit.Type()) {
+		return false
+	}
+
+	convert, inRange, err := types.Int8.Convert(lit.Value())
+	if err != nil {
+		// Ignore any conversion errors, since that means the value isn't 0
+		// and the values are validated in other parts of the analyzer anyway.
+		return false
+	}
+	return bool(inRange) && convert == int8(0)
+}
+
 // insertAutoUuidExpression transforms the specified |expr| for |autoUuidCol| and inserts an AutoUuid
 // expression above the UUID() function call, so that the auto generated UUID value can be captured and
 // saved to the session's query info.