Do not fuzz CREATE queries

We don't do it anyway, the first unmodified query succeeds and all
others fail. Just make it official.

programs/client/Client.cpp

@@ -57,7 +57,7 @@
 #include <DataStreams/AsynchronousBlockInputStream.h>
 #include <DataStreams/AddingDefaultsBlockInputStream.h>
 #include <DataStreams/InternalTextLogsRowOutputStream.h>
-#include <Parsers/ParserQuery.h>
+#include <Parsers/ASTCreateQuery.h>
 #include <Parsers/ASTSetQuery.h>
 #include <Parsers/ASTUseQuery.h>
 #include <Parsers/ASTInsertQuery.h>
@@ -67,6 +67,7 @@
 #include <Parsers/ASTIdentifier.h>
 #include <Parsers/formatAST.h>
 #include <Parsers/parseQuery.h>
+#include <Parsers/ParserQuery.h>
 #include <Interpreters/Context.h>
 #include <Interpreters/InterpreterSetQuery.h>
 #include <Interpreters/ReplaceQueryParameterVisitor.h>
@@ -1040,9 +1041,21 @@ private:
             full_query = text.substr(this_query_begin - text.data(),
                 begin - text.data());
 
+            // Don't repeat inserts, the tables grow too big. Also don't repeat
+            // creates because first we run the unmodified query, it will succeed,
+            // and the subsequent queries will fail. When we run out of fuzzer
+            // errors, it may be interesting to add fuzzing of create queries that
+            // wraps columns into LowCardinality or Nullable. Also there are other
+            // kinds of create queries such as CREATE DICTIONARY, we could fuzz
+            // them as well.
+            int this_query_runs = query_fuzzer_runs;
+            if (as_insert
+                || orig_ast->as<ASTCreateQuery>())
+            {
+                this_query_runs = 1;
+            }
+
             ASTPtr fuzz_base = orig_ast;
-            // Don't repeat inserts, the tables grow too big.
-            const int this_query_runs = as_insert ? 1 : query_fuzzer_runs;
             for (int fuzz_step = 0; fuzz_step < this_query_runs; fuzz_step++)
             {
                 fprintf(stderr, "fuzzing step %d out of %d for query at pos %zd\n",