diff --git a/meson.build b/meson.build
index b59855a712538143a20cb5c55292790450125ccc..74234a1fc6bb3e73bb9893c6609f648de05b3513 100644
--- a/meson.build
+++ b/meson.build
@@ -1,6 +1,6 @@
 # -*- mode: conf -*-
 project('zero-pinyin-service', ['c', 'cpp'],
-  version: '0.2.0',
+  version: '0.2.1',
   license: 'GPL',
   default_options: [
     'warning_level=2',
diff --git a/zero-pinyin-service.c b/zero-pinyin-service.c
index ddc17a6d7993304906579c3c7f4cabc1aba89f02..17545320eeac201de4a6f46337706870325bce87 100644
--- a/zero-pinyin-service.c
+++ b/zero-pinyin-service.c
@@ -85,9 +85,10 @@ build_sql_for_n_pinyin (GList* pylist,
 			const guint n,
 			const guint limit)
 {
+	/* always keep one space after current term */
 	GString* sql = NULL;
 	gchar* where_clause = NULL;
-	sql = g_string_new ("SELECT user_freq, phrase, freq FROM (");
+	sql = g_string_new (NULL);
 	g_string_append_printf (
 		sql, "SELECT 0 AS user_freq, phrase, freq FROM "
 		"maindb.py_phrase_%u WHERE ", n - 1);
@@ -95,13 +96,13 @@ build_sql_for_n_pinyin (GList* pylist,
 	g_assert_nonnull (where_clause);
 	g_message ("where_clause=%s", where_clause);
 	sql = g_string_append (sql, where_clause);
-	sql = g_string_append (sql, " UNION ");
+	sql = g_string_append (sql, "UNION ");
 	g_string_append_printf (
 		sql, "SELECT user_freq, phrase, freq FROM "
 		"userdb.py_phrase_%u WHERE ", n - 1);
 	sql = g_string_append (sql, where_clause);
-	sql = g_string_append (sql, ") GROUP BY phrase ORDER BY user_freq DESC, freq DESC ");
-	g_string_append_printf (sql, "LIMIT %u", limit);
+	sql = g_string_append (sql, "GROUP BY phrase ORDER BY user_freq DESC, freq DESC ");
+	g_string_append_printf (sql, "LIMIT %u;", limit);
 	char* result = sql->str;
 	g_free (where_clause);
 	g_string_free (sql, FALSE);
@@ -149,13 +150,13 @@ get_candidates_for_n_pinyin (sqlite3* db,
 	const char* unused;
 	Candidate* c = NULL;
 	r = sqlite3_prepare_v2 (db, sql, -1, &stmt, &unused);
-	g_free (sql);
 	g_assert_nonnull (unused);
 	g_assert_cmpstr (unused, ==, "");
 	if (strlen (unused)) {
 		g_warning ("part of sql is unused \"%s\" length=%zu",
 			   unused, strlen (unused));
 	}
+	g_free (sql);
 	while (TRUE) {
 		r = sqlite3_step (stmt);
 		if (r == SQLITE_DONE) {