diff --git a/cmd/sqlcmd/sqlcmd.go b/cmd/sqlcmd/sqlcmd.go
index 5abc0860..c027036f 100644
--- a/cmd/sqlcmd/sqlcmd.go
+++ b/cmd/sqlcmd/sqlcmd.go
@@ -359,20 +359,20 @@ func checkDefaultValue(args []string, i int) (val string) {
 		'L': "|", // | is the sentinel for no value since users are unlikely to use it. It's "reserved" in most shells
 		'X': "0",
 	}
-	if isFlag(args[i]) && len(args[i]) == 2 && (len(args) == i+1 || args[i+1][0] == '-') {
+	if isFlag(args[i]) && len(args[i]) == 2 && (len(args) == i+1 || isFlag(args[i+1])) {
 		if v, ok := flags[rune(args[i][1])]; ok {
 			val = v
 			return
 		}
 	}
-	if args[i] == "-N" && (len(args) == i+1 || args[i+1][0] == '-') {
+	if args[i] == "-N" && (len(args) == i+1 || isFlag(args[i+1])) {
 		val = "true"
 	}
 	return
 }
 
 func isFlag(arg string) bool {
-	return arg[0] == '-'
+	return len(arg) > 0 && arg[0] == '-'
 }
 
 func isListFlag(arg string) bool {
diff --git a/cmd/sqlcmd/sqlcmd_test.go b/cmd/sqlcmd/sqlcmd_test.go
index 4554998a..44326c18 100644
--- a/cmd/sqlcmd/sqlcmd_test.go
+++ b/cmd/sqlcmd/sqlcmd_test.go
@@ -584,11 +584,16 @@ func TestConvertOsArgs(t *testing.T) {
 			[]string{"-X", "-k2"},
 			[]string{"-X", "0", "-k2"},
 		},
+		{
+			"flag with empty value",
+			[]string{"-S", "server", "-U", "sa", "-d", "", "-Q", "SELECT 1", "-b"},
+			[]string{"-S", "server", "-U", "sa", "-d", "", "-Q", "SELECT 1", "-b"},
+		},
 	}
 	for _, c := range tests {
 		t.Run(c.name, func(t *testing.T) {
 			actual := convertOsArgs(c.in)
-			assert.ElementsMatch(t, c.expected, actual, "Incorrect converted args")
+			assert.Equal(t, c.expected, actual, "Incorrect converted args")
 		})
 	}
 }