Index: src/func.c
==================================================================
--- src/func.c
+++ src/func.c
@@ -1539,11 +1539,13 @@
       }
       if( nSep ) sqlite3StrAccumAppend(pAccum, zSep, nSep);
     }
     zVal = (char*)sqlite3_value_text(argv[0]);
     nVal = sqlite3_value_bytes(argv[0]);
-    if( nVal ) sqlite3StrAccumAppend(pAccum, zVal, nVal);
+    if( nVal || (zVal="", firstTerm) ){
+      sqlite3StrAccumAppend(pAccum, zVal, nVal);
+    }
   }
 }
 static void groupConcatFinalize(sqlite3_context *context){
   StrAccum *pAccum;
   pAccum = sqlite3_aggregate_context(context, 0);

Index: test/func.test
==================================================================
--- test/func.test
+++ test/func.test
@@ -1192,10 +1192,22 @@
   execsql {
     SELECT group_concat(CASE t1 WHEN 'this' THEN ''
                           WHEN 'program' THEN null ELSE t1 END) FROM tbl1
   }
 } {,is,free,software}
+# Tests to verify ticket http://www.sqlite.org/src/tktview/55746f9e65f8587c0
+do_test func-24.13 {
+  execsql {
+    SELECT typeof(group_concat(x)) FROM (SELECT '' AS x);
+  }
+} {text}
+do_test func-24.14 {
+  execsql {
+    SELECT typeof(group_concat(x,''))
+      FROM (SELECT '' AS x UNION ALL SELECT '');
+  }
+} {text}
 
 
 # Use the test_isolation function to make sure that type conversions
 # on function arguments do not effect subsequent arguments.
 #