SQLite

** "Select Flag".
**
** Value constraints (all checked via assert())
**     SF_HasAgg     == NC_HasAgg
**     SF_MinMaxAgg  == NC_MinMaxAgg     == SQLITE_FUNC_MINMAX
**     SF_FixedLimit == WHERE_USE_LIMIT
*/
#define SF_Distinct      0x0000001 /* Output should be DISTINCT */
#define SF_All           0x0000002 /* Includes the ALL keyword */
#define SF_Resolved      0x0000004 /* Identifiers have been resolved */
#define SF_Aggregate     0x0000008 /* Contains agg functions or a GROUP BY */
#define SF_HasAgg        0x0000010 /* Contains aggregate functions */
#define SF_UsesEphemeral 0x0000020 /* Uses the OpenEphemeral opcode */
#define SF_Expanded      0x0000040 /* sqlite3SelectExpand() called on this */
#define SF_HasTypeInfo   0x0000080 /* FROM subqueries have Table metadata */
#define SF_Compound      0x0000100 /* Part of a compound query */
#define SF_Values        0x0000200 /* Synthesized from VALUES clause */
#define SF_MultiValue    0x0000400 /* Single VALUES term with multiple rows */
#define SF_NestedFrom    0x0000800 /* Part of a parenthesized FROM clause */
#define SF_MinMaxAgg     0x0001000 /* Aggregate containing min() or max() */
#define SF_Recursive     0x0002000 /* The recursive part of a recursive CTE */
#define SF_FixedLimit    0x0004000 /* nSelectRow set by a constant LIMIT */
#define SF_MaybeConvert  0x0008000 /* Need convertCompoundSelectToSubquery() */
#define SF_Converted     0x0010000 /* By convertCompoundSelectToSubquery() */
#define SF_IncludeHidden 0x0020000 /* Include hidden columns in output */
#define SF_ComplexResult 0x0040000 /* Result contains subquery or function */
#define SF_WhereBegin    0x0080000 /* Really a WhereBegin() call.  Debug Only */
#define SF_WinRewrite    0x0100000 /* Window function rewrite accomplished */

/*
** The results of a SELECT can be distributed in several ways, as defined
** by one of the following macros.  The "SRT" prefix means "SELECT Result
** Type".
**
**     SRT_Union       Store results as a key in a temporary index

** any SQL window functions, this function is a no-op. Otherwise, it 
** rewrites the SELECT statement so that window function xStep functions
** are invoked in the correct order as described under "SELECT REWRITING"
** at the top of this file.
*/
int sqlite3WindowRewrite(Parse *pParse, Select *p){
  int rc = SQLITE_OK;
  if( p->pWin && p->pPrior==0 && (p->selFlags & SF_WinRewrite)==0 ){
    Vdbe *v = sqlite3GetVdbe(pParse);
    sqlite3 *db = pParse->db;
    Select *pSub = 0;             /* The subquery */
    SrcList *pSrc = p->pSrc;
    Expr *pWhere = p->pWhere;
    ExprList *pGroupBy = p->pGroupBy;
    Expr *pHaving = p->pHaving;

    }

    p->pSrc = 0;
    p->pWhere = 0;
    p->pGroupBy = 0;
    p->pHaving = 0;
    p->selFlags &= ~SF_Aggregate;
    p->selFlags |= SF_WinRewrite;

    /* Create the ORDER BY clause for the sub-select. This is the concatenation
    ** of the window PARTITION and ORDER BY clauses. Then, if this makes it
    ** redundant, remove the ORDER BY from the parent SELECT.  */
    pSort = sqlite3ExprListDup(db, pMWin->pPartition, 0);
    pSort = exprListAppendList(pParse, pSort, pMWin->pOrderBy, 1);
    if( pSort && p->pOrderBy && p->pOrderBy->nExpr<=pSort->nExpr ){