diff --git a/src/frontend/sql/query.pest b/src/frontend/sql/query.pest
index 6eb4c9b0d9ab8b6720236b568015277af42cf027..cd74e2ed33699a0bcf013f8a0e0e0b7df4aaba4a 100644
--- a/src/frontend/sql/query.pest
+++ b/src/frontend/sql/query.pest
@@ -72,7 +72,7 @@ Expr = _{  Or | And | Unary | Between | Cmp | Primary | Parentheses }
 
 
 NameString = @{ !(WHITESPACE* ~ Keyword ~ WHITESPACE) ~ ('А' .. 'Я' | 'а' .. 'я' | 'A' .. 'Z' | 'a'..'z' | "-" | "_" | ASCII_DIGIT)+ }
-String = @{ !(WHITESPACE* ~ Keyword ~ WHITESPACE) ~ (Character | ("'" ~ "'") | "\"")+ }
+String = @{ !(WHITESPACE* ~ Keyword ~ WHITESPACE) ~ (Character | ("'" ~ "'") | "\"")* }
 Keyword = { ^"except" | ^"union" | ^"where" }
 Character = _{ ASCII_ALPHANUMERIC | 'А' .. 'Я' | 'а' .. 'я' | Other | Punctuation | SYMBOL }
 Punctuation = _{
diff --git a/test_app/test/integration/api_test.lua b/test_app/test/integration/api_test.lua
index 4278b23d4b6abd7e3012788da9f61de75965f5fd..a93b6d33a485bf042d2b202a8ed423407d6a7fb5 100644
--- a/test_app/test/integration/api_test.lua
+++ b/test_app/test/integration/api_test.lua
@@ -694,6 +694,34 @@ g.test_insert_6 = function()
     })
 end
 
+-- check empty string
+g.test_insert_7 = function()
+    local api = cluster:server("api-1").net_box
+
+    local r, err = api:call("sbroad.execute", { [[INSERT INTO "space_simple_shard_key"
+    ("sysOp", "id", "name") VALUES (8, 8, '')]], {} })
+
+    t.assert_equals(err, nil)
+    t.assert_equals(r, {row_count = 1})
+
+    r, err = api:call("sbroad.execute", { [[SELECT *, "bucket_id" FROM "space_simple_shard_key"]], {} })
+
+    t.assert_equals(err, nil)
+    t.assert_equals(r, {
+        metadata = {
+            {name = "id", type = "integer"},
+            {name = "name", type = "string"},
+            {name = "sysOp", type = "integer"},
+            {name = "bucket_id", type = "unsigned"},
+        },
+        rows = {
+            {1, "ok", 1, 3940},
+            {8, "", 8, 12104},
+            {10, box.NULL, 0, 11520}
+        },
+    })
+end
+
 g.test_decimal_double = function()
     local api = cluster:server("api-1").net_box