From f22779ad15c6be57a7d2ff2b9423b796f091725c Mon Sep 17 00:00:00 2001
From: hotid <igorsd@igorsd.ru>
Date: Fri, 26 Oct 2018 20:14:43 +0300
Subject: [PATCH] stop generating empty WHERE () section in mysql queries

---
 dbms/src/Storages/transformQueryForExternalDatabase.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/dbms/src/Storages/transformQueryForExternalDatabase.cpp b/dbms/src/Storages/transformQueryForExternalDatabase.cpp
index 2615e8d0d92..43d20d7a4c0 100644
--- a/dbms/src/Storages/transformQueryForExternalDatabase.cpp
+++ b/dbms/src/Storages/transformQueryForExternalDatabase.cpp
@@ -119,6 +119,7 @@ String transformQueryForExternalDatabase(
         {
             if (function->name == "and")
             {
+                bool compatibleFound = false;
                 auto new_function_and = std::make_shared<ASTFunction>();
                 auto new_function_and_arguments = std::make_shared<ASTExpressionList>();
                 new_function_and->arguments = new_function_and_arguments;
@@ -126,9 +127,13 @@ String transformQueryForExternalDatabase(
 
                 for (const auto & elem : function->arguments->children)
                     if (isCompatible(*elem))
+                    {
                         new_function_and_arguments->children.push_back(elem);
+                        compatibleFound = true;
+                    }
 
-                select->where_expression = std::move(new_function_and);
+                if (compatibleFound)
+                     select->where_expression = std::move(new_function_and);
             }
         }
     }