diff --git a/hikyuu/utilities/db_connect/mysql/MySQLStatement.cpp b/hikyuu/utilities/db_connect/mysql/MySQLStatement.cpp
index 400b6a5..8598f66 100755
--- a/hikyuu/utilities/db_connect/mysql/MySQLStatement.cpp
+++ b/hikyuu/utilities/db_connect/mysql/MySQLStatement.cpp
@@ -416,7 +416,11 @@ void MySQLStatement::sub_getColumnAsBlob(int idx, std::vector<char>& item) {
     }
 
     try {
-        item = boost::any_cast<std::vector<char>>(m_result_buffer[idx]);
+        unsigned long len = m_result_length[idx];
+        std::vector<char>* p = boost::any_cast<std::vector<char>>(&m_result_buffer[idx]);
+        item.resize(len);
+        memcpy(item.data(), p->data(), len);
+
     } catch (...) {
         HKU_THROW("Field type mismatch! idx: {}", idx);
     }