Index: src/where.c
==================================================================
--- src/where.c
+++ src/where.c
@@ -2906,14 +2906,14 @@
                            WO_EQ|WO_ISNULL|WO_IN, pIdx);
     if( pConstraint==0 ){
       isEq = 0;
     }else if( pConstraint->eOperator==WO_IN ){
       break;
-    }else if( pConstraint->prereqRight==0 ){
-      isEq = 1;
     }else if( pConstraint->eOperator==WO_ISNULL ){
       uniqueNotNull = 0;
+      isEq = 1;
+    }else if( pConstraint->prereqRight==0 ){
       isEq = 1;
     }else{
       Expr *pRight = pConstraint->pExpr->pRight;
       if( pRight->op==TK_COLUMN ){
         WHERETRACE(("       .. isOrderedColumn(tab=%d,col=%d)",
@@ -2933,21 +2933,23 @@
       if( isEq==0 ){
         break;
       }else{
         continue;
       }
-    }else if( sortOrder==2 ){
-      sortOrder = termSortOrder;
-    }else if( termSortOrder!=sortOrder ){
-      break;
+    }else if( isEq!=1 ){
+      if( sortOrder==2 ){
+        sortOrder = termSortOrder;
+      }else if( termSortOrder!=sortOrder ){
+        break;
+      }
     }
     j++;
     pOBItem++;
     if( iColumn<0 ){
       seenRowid = 1;
       break;
-    }else if( pTab->aCol[iColumn].notNull==0 ){
+    }else if( pTab->aCol[iColumn].notNull==0 && isEq==0 ){
       uniqueNotNull = 0;
     }
   }
 
   /* If we have not found at least one ORDER BY term that matches the