Index: src/vdbe.c
==================================================================
--- src/vdbe.c
+++ src/vdbe.c
@@ -2815,14 +2815,26 @@
   while( 1 /*exit-by-break*/ ){
     assert( pIn1 <= &p->aMem[(p->nMem+1 - p->nCursor)] );
     assert( memIsValid(pIn1) );
     applyAffinity(pIn1, zAffinity[0], encoding);
     if( zAffinity[0]==SQLITE_AFF_REAL && (pIn1->flags & MEM_Int)!=0 ){
-      /* When applying REAL affinity, if the result is still MEM_Int, 
-      ** indicate that REAL is actually desired */
-      pIn1->flags |= MEM_IntReal;
-      pIn1->flags &= ~MEM_Int;
+      /* When applying REAL affinity, if the result is still an MEM_Int
+      ** that will fit in 6 bytes, then change the type to MEM_IntReal
+      ** so that we keep the high-resolution integer value but know that
+      ** the type really wants to be REAL. */
+      testcase( pIn1->u.i==140737488355328LL );
+      testcase( pIn1->u.i==140737488355327LL );
+      testcase( pIn1->u.i==-140737488355328LL );
+      testcase( pIn1->u.i==-140737488355329LL );
+      if( pIn1->u.i<=140737488355327LL && pIn1->u.i>=-140737488355328LL ){
+        pIn1->flags |= MEM_IntReal;
+        pIn1->flags &= ~MEM_Int;
+      }else{
+        pIn1->u.r = (double)pIn1->u.i;
+        pIn1->flags |= MEM_Real;
+        pIn1->flags &= ~MEM_Int;
+      }
     }
     REGISTER_TRACE((int)(pIn1-aMem), pIn1);
     zAffinity++;
     if( zAffinity[0]==0 ) break;
     pIn1++;

Index: test/intreal.test
==================================================================
--- test/intreal.test
+++ test/intreal.test
@@ -80,7 +80,19 @@
         t1.c1 >= CAST(8366271098608253588 AS REAL) 
     AND t1.c1 <= CAST(8366271098608253588 AS REAL)
   );
 } [list a $D]
 
+# 2019-07-29 ticket ba2f4585cf495231
+#
+db close
+sqlite3 db :memory:
+do_execsql_test 3.0 {
+  CREATE TABLE t0 (c0 REAL, c1);
+  CREATE UNIQUE INDEX i0 ON t0(c1, 0 | c0);
+  INSERT INTO t0(c0) VALUES (4750228396194493326), (0);
+  UPDATE OR REPLACE t0 SET c0 = 'a', c1 = '';
+  SELECT * FROM t0 ORDER BY t0.c1;
+  PRAGMA integrity_check;
+} {a {} ok}
 
 finish_test