Use the estimated number of rows computed for subqueries in the cost

computations for outer queries.

FossilOrigin-Name: 56bbc539246a6dc9f1ae1edb898db7a4f6f6d322

src/sqliteInt.h

@@ -1947,6 +1947,7 @@ struct WhereInfo {
   int nLevel;                    /* Number of nested loop */
   struct WhereClause *pWC;       /* Decomposition of the WHERE clause */
   double savedNQueryLoop;        /* pParse->nQueryLoop outside the WHERE loop */
+  double nRowOut;                /* Estimated number of output rows */
   WhereLevel a[1];               /* Information about each nest loop in WHERE */
 };
 
@@ -2022,6 +2023,7 @@ struct Select {
   Expr *pOffset;         /* OFFSET expression. NULL means not used. */
   int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */
   int addrOpenEphm[3];   /* OP_OpenEphem opcodes related to this select */
+  double nSelectRow;     /* Estimated number of result rows */
 };
 
 /*