diff --git a/src/box/sql/func.c b/src/box/sql/func.c
index 761a3abae5c22195bf8acf8ea9bb608716c0d653..98cad51fd2a7eeb7075e357c6227731939c1f728 100644
--- a/src/box/sql/func.c
+++ b/src/box/sql/func.c
@@ -1893,6 +1893,9 @@ sqlRegisterBuiltinFunctions(void)
 			  FIELD_TYPE_STRING),
 		FUNCTION2(length, 1, 0, 0, lengthFunc, SQL_FUNC_LENGTH,
 			  FIELD_TYPE_INTEGER),
+		FUNCTION(char_length, 1, 0, 0, lengthFunc, FIELD_TYPE_INTEGER),
+		FUNCTION(character_length, 1, 0, 0, lengthFunc,
+			 FIELD_TYPE_INTEGER),
 		FUNCTION(position, 2, 0, 1, position_func, FIELD_TYPE_INTEGER),
 		FUNCTION(printf, -1, 0, 0, printfFunc, FIELD_TYPE_STRING),
 		FUNCTION(unicode, 1, 0, 0, unicodeFunc, FIELD_TYPE_STRING),
diff --git a/test/sql-tap/func3.test.lua b/test/sql-tap/func3.test.lua
index 6d6411ca6edee5282c9da86ba17960eb8aed8387..2d0579d931ed3f2e3d4aac018389f548bc8d5386 100755
--- a/test/sql-tap/func3.test.lua
+++ b/test/sql-tap/func3.test.lua
@@ -1,6 +1,6 @@
 #!/usr/bin/env tarantool
 test = require("sqltester")
-test:plan(25)
+test:plan(35)
 
 --!./tcltestrunner.lua
 -- 2010 August 27
@@ -285,5 +285,26 @@ test:do_test(
     end, test:execsql "EXPLAIN SELECT min(1.0+'2.0',4*11)")
 
 
+--
+-- gh-3929: sql: ANSI aliases for LENGTH().
+--
+suits = {}
+suits[1] = {str = '123456789', len = 9}
+suits[2] = {str = '\x80', len = 1}
+suits[3] = {str = '\x61\x62\x63', len = 3}
+suits[4] = {str = '\x7f\x80\x81', len = 3}
+suits[5] = {str = '\x61\xc0', len = 2}
+suits[6] = {str = '\x61\xc0\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80', len = 12}
+suits[7] = {str = '\xc0\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80', len = 11}
+suits[8] = {str = '\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80', len = 10}
+suits[9] = {str = '\x80\x80\x80\x80\x80\xf0\x80\x80\x80\x80', len = 7}
+suits[10] = {str = '\x80\x80\x80\x80\x80\xf0\x80\x80\x80\xff', len = 7}
+
+for k,v in pairs(suits) do
+    test:do_execsql_test(
+        "func3-6."..k,
+        "SELECT CHAR_LENGTH('"..v.str.."'), CHARACTER_LENGTH('"..v.str.."');",
+        {v.len, v.len})
+end
 
 test:finish_test()