commit a3fcc000cb7bd5b12816512834e6484c68658576
author dan <dan@noemail.net> Thu Aug 15 13:53:22 2019 +0000
committer dan <dan@noemail.net> Thu Aug 15 13:53:22 2019 +0000
tree 4120e7f003a337ceab43adeaf2800683143224af
parent d4da4936cdfaf5647d9daf0b861b2e63969a810d

Ensure that SQLite does not attempt to process incompatible window functions in a single scan. Fix for [256741a1].

FossilOrigin-Name: 4f5b2d938194fab7627486e2ced633def2c90d9d3328e3700612feb9dbfa3d9a

src/expr.c

diff --git a/src/expr.c b/src/expr.c
index e00b319..8f02ae5 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -1325,12 +1325,7 @@
     assert( pWin );
     assert( IsWindowFunc(pExpr) );
     assert( pWin->ppThis==0 );
-    if( pSelect->pWin ){
-      pSelect->pWin->ppThis = &pWin->pNextWin;
-    }
-    pWin->pNextWin = pSelect->pWin;
-    pWin->ppThis = &pSelect->pWin;
-    pSelect->pWin = pWin;
+    sqlite3WindowLink(pSelect, pWin);
   }
   return WRC_Continue;
 }

src/resolve.c

diff --git a/src/resolve.c b/src/resolve.c
index d88abc4..3160038 100644
--- a/src/resolve.c
+++ b/src/resolve.c
@@ -908,16 +908,7 @@
           sqlite3WalkExprList(pWalker, pWin->pPartition);
           sqlite3WalkExprList(pWalker, pWin->pOrderBy);
           sqlite3WalkExpr(pWalker, pWin->pFilter);
-          if( 0==pSel->pWin 
-           || 0==sqlite3WindowCompare(pParse, pSel->pWin, pWin, 0)
-          ){
-            pWin->pNextWin = pSel->pWin;
-            if( pSel->pWin ){
-              pSel->pWin->ppThis = &pWin->pNextWin;
-            }
-            pSel->pWin = pWin;
-            pWin->ppThis = &pSel->pWin;
-          }
+          sqlite3WindowLink(pSel, pWin);
           pNC->ncFlags |= NC_HasWin;
         }else
 #endif /* SQLITE_OMIT_WINDOWFUNC */

src/sqliteInt.h

diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 1104b77..d6746aa 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -3609,6 +3609,7 @@
 void sqlite3WindowListDelete(sqlite3 *db, Window *p);
 Window *sqlite3WindowAlloc(Parse*, int, int, Expr*, int , Expr*, u8);
 void sqlite3WindowAttach(Parse*, Expr*, Window*);
+void sqlite3WindowLink(Select *pSel, Window *pWin);
 int sqlite3WindowCompare(Parse*, Window*, Window*, int);
 void sqlite3WindowCodeInit(Parse*, Window*);
 void sqlite3WindowCodeStep(Parse*, Select*, WhereInfo*, int, int);

src/window.c

diff --git a/src/window.c b/src/window.c
index ebcb576..e2f0b62 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1230,6 +1230,25 @@
 }
 
 /*
+** Possibly link window pWin into the list at pSel->pWin (window functions
+** to be processed as part of SELECT statement pSel). The window is linked
+** in if either (a) there are no other windows already linked to this
+** SELECT, or (b) the windows already linked use a compatible window frame.
+*/
+void sqlite3WindowLink(Select *pSel, Window *pWin){
+  if( 0==pSel->pWin 
+   || 0==sqlite3WindowCompare(0, pSel->pWin, pWin, 0)
+  ){
+    pWin->pNextWin = pSel->pWin;
+    if( pSel->pWin ){
+      pSel->pWin->ppThis = &pWin->pNextWin;
+    }
+    pSel->pWin = pWin;
+    pWin->ppThis = &pSel->pWin;
+  }
+}
+
+/*
 ** Return 0 if the two window objects are identical, or non-zero otherwise.
 ** Identical window objects can be processed in a single scan.
 */
@@ -1416,6 +1435,8 @@
     int nArg = windowArgCount(pWin);
     int i;
 
+    assert( bInverse==0 || pWin->eStart!=TK_UNBOUNDED );
+
     for(i=0; i<nArg; i++){
       if( i!=1 || pFunc->zName!=nth_valueName ){
         sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol+i, reg+i);