diff --git a/prepare_stmt.go b/prepare_stmt.go
index 5faea995..88bec4e9 100644
--- a/prepare_stmt.go
+++ b/prepare_stmt.go
@@ -32,14 +32,14 @@ func (db *PreparedStmtDB) GetDBConn() (*sql.DB, error) {
 
 func (db *PreparedStmtDB) Close() {
 	db.Mux.Lock()
+	defer db.Mux.Unlock()
+
 	for _, query := range db.PreparedSQL {
 		if stmt, ok := db.Stmts[query]; ok {
 			delete(db.Stmts, query)
 			go stmt.Close()
 		}
 	}
-
-	db.Mux.Unlock()
 }
 
 func (db *PreparedStmtDB) prepare(ctx context.Context, conn ConnPool, isTransaction bool, query string) (Stmt, error) {
@@ -51,9 +51,10 @@ func (db *PreparedStmtDB) prepare(ctx context.Context, conn ConnPool, isTransact
 	db.Mux.RUnlock()
 
 	db.Mux.Lock()
+	defer db.Mux.Unlock()
+
 	// double check
 	if stmt, ok := db.Stmts[query]; ok && (!stmt.Transaction || isTransaction) {
-		db.Mux.Unlock()
 		return stmt, nil
 	} else if ok {
 		go stmt.Close()
@@ -64,7 +65,6 @@ func (db *PreparedStmtDB) prepare(ctx context.Context, conn ConnPool, isTransact
 		db.Stmts[query] = Stmt{Stmt: stmt, Transaction: isTransaction}
 		db.PreparedSQL = append(db.PreparedSQL, query)
 	}
-	defer db.Mux.Unlock()
 
 	return db.Stmts[query], err
 }
@@ -83,9 +83,9 @@ func (db *PreparedStmtDB) ExecContext(ctx context.Context, query string, args ..
 		result, err = stmt.ExecContext(ctx, args...)
 		if err != nil {
 			db.Mux.Lock()
+			defer db.Mux.Unlock()
 			go stmt.Close()
 			delete(db.Stmts, query)
-			db.Mux.Unlock()
 		}
 	}
 	return result, err
@@ -97,9 +97,10 @@ func (db *PreparedStmtDB) QueryContext(ctx context.Context, query string, args .
 		rows, err = stmt.QueryContext(ctx, args...)
 		if err != nil {
 			db.Mux.Lock()
+			defer db.Mux.Unlock()
+
 			go stmt.Close()
 			delete(db.Stmts, query)
-			db.Mux.Unlock()
 		}
 	}
 	return rows, err
@@ -138,9 +139,10 @@ func (tx *PreparedStmtTX) ExecContext(ctx context.Context, query string, args ..
 		result, err = tx.Tx.StmtContext(ctx, stmt.Stmt).ExecContext(ctx, args...)
 		if err != nil {
 			tx.PreparedStmtDB.Mux.Lock()
+			defer tx.PreparedStmtDB.Mux.Unlock()
+
 			go stmt.Close()
 			delete(tx.PreparedStmtDB.Stmts, query)
-			tx.PreparedStmtDB.Mux.Unlock()
 		}
 	}
 	return result, err
@@ -152,9 +154,10 @@ func (tx *PreparedStmtTX) QueryContext(ctx context.Context, query string, args .
 		rows, err = tx.Tx.Stmt(stmt.Stmt).QueryContext(ctx, args...)
 		if err != nil {
 			tx.PreparedStmtDB.Mux.Lock()
+			defer tx.PreparedStmtDB.Mux.Unlock()
+
 			go stmt.Close()
 			delete(tx.PreparedStmtDB.Stmts, query)
-			tx.PreparedStmtDB.Mux.Unlock()
 		}
 	}
 	return rows, err
diff --git a/statement.go b/statement.go
index 347f88ff..3b76f653 100644
--- a/statement.go
+++ b/statement.go
@@ -271,13 +271,19 @@ func (stmt *Statement) BuildCondition(query interface{}, args ...interface{}) []
 		if _, err := strconv.Atoi(s); err != nil {
 			if s == "" && len(args) == 0 {
 				return nil
-			} else if len(args) == 0 || (len(args) > 0 && strings.Contains(s, "?")) {
+			}
+
+			if len(args) == 0 || (len(args) > 0 && strings.Contains(s, "?")) {
 				// looks like a where condition
 				return []clause.Expression{clause.Expr{SQL: s, Vars: args}}
-			} else if len(args) > 0 && strings.Contains(s, "@") {
+			}
+
+			if len(args) > 0 && strings.Contains(s, "@") {
 				// looks like a named query
 				return []clause.Expression{clause.NamedExpr{SQL: s, Vars: args}}
-			} else if len(args) == 1 {
+			}
+
+			if len(args) == 1 {
 				return []clause.Expression{clause.Eq{Column: s, Value: args[0]}}
 			}
 		}