diff --git a/graphql/query_to_avro.lua b/graphql/query_to_avro.lua
index 3843a55..ff68c30 100644
--- a/graphql/query_to_avro.lua
+++ b/graphql/query_to_avro.lua
@@ -135,18 +135,22 @@ object_to_avro = function(object_type, selections, context)
     return result
 end
 
---- Create an Avro schema for a given query.
+--- Create an Avro schema for a given query / operation.
 ---
---- @tparam table query object which avro schema should be created for
+--- @tparam table qstate compiled query for which the avro schema should be
+--- created
 ---
---- @treturn table `avro_schema` avro schema for any `query:execute()` result
-function query_to_avro.convert(query)
-    assert(type(query) == "table",
-        ('query should be a table, got: %s; ' ..
+--- @tparam[opt] string operation_name optional operation name
+---
+--- @treturn table `avro_schema` avro schema for any
+--- `qstate:execute(..., operation_name)` result
+function query_to_avro.convert(qstate, operation_name)
+    assert(type(qstate) == "table",
+        ('qstate should be a table, got: %s; ' ..
         'hint: use ":" instead of "."'):format(type(table)))
-    local state = query.state
-    local context = query_util.buildContext(state.schema, query.ast, {}, {},
-        query.operation_name)
+    local state = qstate.state
+    local context = query_util.buildContext(state.schema, qstate.ast, {}, {},
+        operation_name)
     -- The variable is necessary to avoid fullname interferention.
     -- Each nested Avro record creates it's namespace.
     context.namespace_parts = {}
diff --git a/graphql/server/server.lua b/graphql/server/server.lua
index 4c7429f..ae58b25 100644
--- a/graphql/server/server.lua
+++ b/graphql/server/server.lua
@@ -107,7 +107,14 @@ function server.init(graphql, host, port)
             }
         end
 
-        local ok, result = pcall(compiled_query.execute, compiled_query, variables)
+        local operation_name = parsed.operationName
+        -- box.NULL -> nil
+        if operation_name == nil then
+            operation_name = nil
+        end
+
+        local ok, result = pcall(compiled_query.execute, compiled_query,
+            variables, operation_name)
         if not ok then
             return {
                 status = 200,
diff --git a/graphql/tarantool_graphql.lua b/graphql/tarantool_graphql.lua
index fb579a5..2465d77 100644
--- a/graphql/tarantool_graphql.lua
+++ b/graphql/tarantool_graphql.lua
@@ -1617,64 +1617,67 @@ local function parse_cfg(cfg)
     return state
 end
 
---- The function just makes some reasonable assertions on input
---- and then call graphql-lua execute.
-local function gql_execute(qstate, variables)
+--- Execute an operation from compiled query.
+---
+--- @tparam qstate compiled query
+---
+--- @tparam variables variables to pass to the query
+---
+--- @tparam[opt] string operation_name optional operation name
+---
+--- @treturn table result of the operation
+local function gql_execute(qstate, variables, operation_name)
     assert(qstate.state)
     local state = qstate.state
     assert(state.schema)
 
-    assert(type(variables) == 'table', 'variables must be table, got ' ..
-        type(variables))
+    check(variables, 'variables', 'table')
+    check(operation_name, 'operation_name', 'string', 'nil')
 
     local root_value = {}
-    local operation_name = qstate.operation_name
-    assert(type(operation_name) == 'string',
-        'operation_name must be a string, got ' .. type(operation_name))
 
     return execute(state.schema, qstate.ast, root_value, variables,
         operation_name)
 end
 
-local function compile_and_execute(state, query, variables)
+--- Compile a query and execute an operation.
+---
+--- See @{gql_compile} and @{gql_execute} for parameters description.
+---
+--- @treturn table result of the operation
+local function compile_and_execute(state, query, variables, operation_name)
     assert(type(state) == 'table', 'use :gql_execute(...) instead of ' ..
         '.execute(...)')
+    assert(state.schema ~= nil, 'have not compiled schema')
     check(query, 'query', 'string')
     check(variables, 'variables', 'table', 'nil')
+    check(operation_name, 'operation_name', 'string', 'nil')
+
     local compiled_query = state:compile(query)
-    return compiled_query:execute(variables)
+    return compiled_query:execute(variables, operation_name)
 end
 
---- The function parses a query string, validate the resulting query
---- against the GraphQL schema and provides an object with the function to
---- execute the query with specific variables values.
+--- Parse GraphQL query string, validate against the GraphQL schema and
+--- provide an object with the function to execute an operation from the
+--- request with specific variables values.
 ---
---- @tparam table state current state of graphql, including
---- schemas, collections and accessor
---- @tparam string query query string
+--- @tparam table state a tarantool_graphql instance
+---
+--- @tparam string query text of a GraphQL query
+---
+--- @treturn table compiled query with `execute` and `avro_schema` functions
 local function gql_compile(state, query)
     assert(type(state) == 'table' and type(query) == 'string',
         'use :validate(...) instead of .validate(...)')
     assert(state.schema ~= nil, 'have not compiled schema')
+    check(query, 'query', 'string')
 
     local ast = parse(query)
-
-    local operation_name
-    for _, definition in pairs(ast.definitions) do
-        if definition.kind == 'operation' then
-            operation_name = definition.name.value
-        end
-    end
-
-    assert(operation_name, "there is no 'operation' in query " ..
-        "definitions:\n" .. yaml.encode(ast))
-
     validate(state.schema, ast)
 
     local qstate = {
         state = state,
         ast = ast,
-        operation_name = operation_name,
     }
 
     local gql_query = setmetatable(qstate, {
@@ -1719,11 +1722,11 @@ function tarantool_graphql.compile(query)
     return default_instance:compile(query)
 end
 
-function tarantool_graphql.execute(query, variables)
+function tarantool_graphql.execute(query, variables, operation_name)
     if default_instance == nil then
         default_instance = tarantool_graphql.new()
     end
-    return default_instance:execute(query, variables)
+    return default_instance:execute(query, variables, operation_name)
 end
 
 function tarantool_graphql.start_server()
diff --git a/test/testdata/common_testdata.lua b/test/testdata/common_testdata.lua
index 4c568f1..88a952c 100644
--- a/test/testdata/common_testdata.lua
+++ b/test/testdata/common_testdata.lua
@@ -311,7 +311,7 @@ end
 
 function common_testdata.run_queries(gql_wrapper)
     local test = tap.test('common')
-    test:plan(18)
+    test:plan(24)
 
     local query_1 = [[
         query user_by_order($order_id: String) {
@@ -338,13 +338,116 @@ function common_testdata.run_queries(gql_wrapper)
             first_name: Ivan
     ]]):strip())
 
+    local variables_1 = {order_id = 'order_id_1'}
+
     utils.show_trace(function()
-        local variables_1 = {order_id = 'order_id_1'}
         local gql_query_1 = gql_wrapper:compile(query_1)
         local result = gql_query_1:execute(variables_1)
         test:is_deeply(result, exp_result_1, '1')
     end)
 
+    local query_1n = [[
+        query($order_id: String) {
+            order_collection(order_id: $order_id) {
+                order_id
+                description
+                user_connection {
+                    user_id
+                    last_name
+                    first_name
+                }
+            }
+        }
+    ]]
+
+    utils.show_trace(function()
+        local gql_query_1n = gql_wrapper:compile(query_1n)
+        local result = gql_query_1n:execute(variables_1)
+        test:is_deeply(result, exp_result_1, '1n')
+    end)
+
+    local query_1inn = [[
+        {
+            order_collection(order_id: "order_id_1") {
+                order_id
+                description
+                user_connection {
+                    user_id
+                    last_name
+                    first_name
+                }
+            }
+        }
+    ]]
+
+    utils.show_trace(function()
+        local gql_query_1inn = gql_wrapper:compile(query_1inn)
+        local result = gql_query_1inn:execute({})
+        test:is_deeply(result, exp_result_1, '1inn')
+    end)
+
+    local query_1tn = [[
+        query get_order {
+            order_collection(order_id: "order_id_1") {
+                order_id
+                description
+            }
+        }
+        query {
+            order_collection(order_id: "order_id_1") {
+                order_id
+                description
+            }
+        }
+    ]]
+
+    local err_exp = 'Cannot have more than one operation when using ' ..
+        'anonymous operations'
+    local ok, err = pcall(gql_wrapper.compile, gql_wrapper, query_1tn)
+    test:is_deeply({ok, test_utils.strip_error(err)}, {false, err_exp},
+        'unnamed query should be a single one')
+
+    local query_1t = [[
+        query user_by_order {
+            order_collection(order_id: "order_id_1") {
+                order_id
+                description
+                user_connection {
+                    user_id
+                    last_name
+                    first_name
+                }
+            }
+        }
+        query get_order {
+            order_collection(order_id: "order_id_1") {
+                order_id
+                description
+            }
+        }
+    ]]
+
+    local gql_query_1t = utils.show_trace(function()
+        return gql_wrapper:compile(query_1t)
+    end)
+
+    local err_exp = 'Operation name must be specified if more than one ' ..
+        'operation exists.'
+    local ok, err = pcall(gql_query_1t.execute, gql_query_1t, {})
+    test:is_deeply({ok, test_utils.strip_error(err)}, {false, err_exp},
+        'non-determined query name should give an error')
+
+    local err_exp = 'Unknown operation "non_existent_operation"'
+    local ok, err = pcall(gql_query_1t.execute, gql_query_1t, {},
+        'non_existent_operation')
+    test:is_deeply({ok, test_utils.strip_error(err)}, {false, err_exp},
+        'wrong operation name should give an error')
+
+    utils.show_trace(function()
+        local result = gql_query_1t:execute({}, 'user_by_order')
+        test:is_deeply(result, exp_result_1, 'execute an operation by name')
+    end)
+
     local query_2 = [[
         query user_order($user_id: String, $first_name: String, $limit: Int,
                 $offset: String) {