Index: src/expr.c
==================================================================
--- src/expr.c
+++ src/expr.c
@@ -3511,10 +3511,16 @@
         assert(TK_NE==OP_Ne); testcase(op==OP_Ne); VdbeCoverageIf(v,op==OP_Ne);
         testcase( regFree1==0 );
         testcase( regFree2==0 );
       }
       break;
+    }
+    case TK_CONCAT: {
+      if( ConstFactorOk(pParse) && sqlite3ExprIsConstantNotJoin(pExpr) ){
+        /* Try to run CONCAT operations at outside the inner loop */
+        return sqlite3ExprCodeAtInit(pParse, pExpr, -1);
+      }
     }
     case TK_AND:
     case TK_OR:
     case TK_PLUS:
     case TK_STAR:
@@ -3522,12 +3528,11 @@
     case TK_REM:
     case TK_BITAND:
     case TK_BITOR:
     case TK_SLASH:
     case TK_LSHIFT:
-    case TK_RSHIFT: 
-    case TK_CONCAT: {
+    case TK_RSHIFT: {
       assert( TK_AND==OP_And );            testcase( op==TK_AND );
       assert( TK_OR==OP_Or );              testcase( op==TK_OR );
       assert( TK_PLUS==OP_Add );           testcase( op==TK_PLUS );
       assert( TK_MINUS==OP_Subtract );     testcase( op==TK_MINUS );
       assert( TK_REM==OP_Remainder );      testcase( op==TK_REM );