SQLite

  db->flags = savedFlags;
  if( pParse->nErr ) return 0;
  while( pSelect->pPrior ) pSelect = pSelect->pPrior;
  pTab = sqlite3DbMallocZero(db, sizeof(Table) );
  if( pTab==0 ){
    return 0;
  }



  pTab->nTabRef = 1;
  pTab->zName = 0;
  pTab->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) );
  sqlite3ColumnsFromExprList(pParse, pSelect->pEList, &pTab->nCol, &pTab->aCol);
  sqlite3SelectAddColumnTypeAndCollation(pParse, pTab, pSelect);
  pTab->iPKey = -1;
  if( db->mallocFailed ){

** selectWindowRewriteExprCb() by selectWindowRewriteEList().
*/
typedef struct WindowRewrite WindowRewrite;
struct WindowRewrite {
  Window *pWin;
  SrcList *pSrc;
  ExprList *pSub;
  Table *pTab;
  Select *pSubSelect;             /* Current sub-select, if any */
};

/*
** Callback function used by selectWindowRewriteEList(). If necessary,
** this function appends to the output expression-list and updates 
** expression (*ppExpr) in place.

        sqlite3ExprDelete(pParse->db, pExpr);
        ExprClearProperty(pExpr, EP_Static);
        memset(pExpr, 0, sizeof(Expr));

        pExpr->op = TK_COLUMN;
        pExpr->iColumn = p->pSub->nExpr-1;
        pExpr->iTable = p->pWin->iEphCsr;
        pExpr->y.pTab = p->pTab;
      }

      break;
    }

    default: /* no-op */
      break;

** appending the new one.
*/
static void selectWindowRewriteEList(
  Parse *pParse, 
  Window *pWin,
  SrcList *pSrc,
  ExprList *pEList,               /* Rewrite expressions in this list */
  Table *pTab,
  ExprList **ppSub                /* IN/OUT: Sub-select expression-list */
){
  Walker sWalker;
  WindowRewrite sRewrite;

  memset(&sWalker, 0, sizeof(Walker));
  memset(&sRewrite, 0, sizeof(WindowRewrite));

  sRewrite.pSub = *ppSub;
  sRewrite.pWin = pWin;
  sRewrite.pSrc = pSrc;
  sRewrite.pTab = pTab;

  sWalker.pParse = pParse;
  sWalker.xExprCallback = selectWindowRewriteExprCb;
  sWalker.xSelectCallback = selectWindowRewriteSelectCb;
  sWalker.u.pRewrite = &sRewrite;

  (void)sqlite3WalkExprList(&sWalker, pEList);

    ExprList *pGroupBy = p->pGroupBy;
    Expr *pHaving = p->pHaving;
    ExprList *pSort = 0;

    ExprList *pSublist = 0;       /* Expression list for sub-query */
    Window *pMWin = p->pWin;      /* Master window object */
    Window *pWin;                 /* Window object iterator */
    Table *pTab;

    pTab = sqlite3DbMallocZero(db, sizeof(Table));
    if( pTab==0 ){
      return SQLITE_NOMEM;
    }

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

    /* 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 ){
      if( sqlite3ExprListCompare(pSort, p->pOrderBy, -1)==0 ){
        sqlite3ExprListDelete(db, p->pOrderBy);
        p->pOrderBy = 0;
      }
    }

    /* Assign a cursor number for the ephemeral table used to buffer rows.
    ** The OpenEphemeral instruction is coded later, after it is known how
    ** many columns the table will have.  */
    pMWin->iEphCsr = pParse->nTab++;
    pParse->nTab += 3;

    selectWindowRewriteEList(pParse, pMWin, pSrc, p->pEList, pTab, &pSublist);
    selectWindowRewriteEList(pParse, pMWin, pSrc, p->pOrderBy, pTab, &pSublist);
    pMWin->nBufferCol = (pSublist ? pSublist->nExpr : 0);

    /* Append the PARTITION BY and ORDER BY expressions to the to the 
    ** sub-select expression list. They are required to figure out where 
    ** boundaries for partitions and sets of peer rows lie.  */
    pSublist = exprListAppendList(pParse, pSublist, pMWin->pPartition, 0);
    pSublist = exprListAppendList(pParse, pSublist, pMWin->pOrderBy, 0);

    }

    pSub = sqlite3SelectNew(
        pParse, pSublist, pSrc, pWhere, pGroupBy, pHaving, pSort, 0, 0
    );
    p->pSrc = sqlite3SrcListAppend(pParse, 0, 0, 0);
    if( p->pSrc ){
      Table *pTab2;
      p->pSrc->a[0].pSelect = pSub;
      sqlite3SrcListAssignCursors(pParse, p->pSrc);
      pSub->selFlags |= SF_Expanded;
      pTab2 = sqlite3ResultSetOfSelect(pParse, pSub);
      if( pTab2==0 ){
        rc = SQLITE_NOMEM;
      }else{
        memcpy(pTab, pTab2, sizeof(Table));
        pTab->tabFlags |= TF_Ephemeral;
        p->pSrc->a[0].pTab = pTab;

        pTab = pTab2;
      }

      sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pMWin->iEphCsr, pSublist->nExpr);
      sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->iEphCsr+1, pMWin->iEphCsr);
      sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->iEphCsr+2, pMWin->iEphCsr);
      sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->iEphCsr+3, pMWin->iEphCsr);
    }else{
      sqlite3SelectDelete(db, pSub);
    }
    if( db->mallocFailed ) rc = SQLITE_NOMEM;
    sqlite3DbFree(db, pTab);
  }

  return rc;
}

/*
** Free the Window object passed as the second argument.

# 2019 June 8
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix window9

ifcapable !windowfunc {
  finish_test
  return
}

do_execsql_test 1.0 {
  CREATE TABLE fruits(
     name TEXT COLLATE NOCASE,
     color TEXT COLLATE NOCASE
  );
}

do_execsql_test 1.1 {
  INSERT INTO fruits (name, color) VALUES ('apple', 'RED');
  INSERT INTO fruits (name, color) VALUES ('APPLE', 'yellow');
  INSERT INTO fruits (name, color) VALUES ('pear', 'YELLOW');
  INSERT INTO fruits (name, color) VALUES ('PEAR', 'green');
}

do_execsql_test 1.2 {
  SELECT name, color, dense_rank() OVER (ORDER BY name) FROM fruits;
} {
  apple RED    1
  APPLE yellow 1
  pear  YELLOW 2
  PEAR  green  2
}

do_execsql_test 1.3 {
  SELECT name, color,
    dense_rank() OVER (PARTITION BY name ORDER BY color)
  FROM fruits;
} {
  apple RED    1 
  APPLE yellow 2 
  PEAR green   1 
  pear YELLOW  2
}

do_execsql_test 1.4 {
  SELECT name, color,
    dense_rank() OVER (ORDER BY name),
    dense_rank() OVER (PARTITION BY name ORDER BY color)
  FROM fruits;
} {
  apple RED    1 1 
  APPLE yellow 1 2 
  PEAR  green  2 1 
  pear  YELLOW 2 2
}

do_execsql_test 1.5 {
  SELECT name, color,
    dense_rank() OVER (ORDER BY name),
    dense_rank() OVER (PARTITION BY name ORDER BY color)
  FROM fruits ORDER BY color;
} {
  PEAR  green  2 1 
  apple RED    1 1 
  APPLE yellow 1 2 
  pear  YELLOW 2 2
}

do_execsql_test 2.0 {
  CREATE TABLE t1(a BLOB, b INTEGER, c COLLATE nocase);
  INSERT INTO t1 VALUES(1, 2, 'abc');
  INSERT INTO t1 VALUES(3, 4, 'ABC');
}

do_execsql_test 2.1.1 {
  SELECT c=='Abc' FROM t1
} {1     1}
do_execsql_test 2.1.2 {
  SELECT c=='Abc', rank() OVER (ORDER BY b) FROM t1
} {1 1   1 2}

do_execsql_test 2.2.1 {
  SELECT b=='2' FROM t1
} {1     0}
do_execsql_test 2.2.2 {
  SELECT b=='2', rank() OVER (ORDER BY a) FROM t1
} {1 1   0 2}

finish_test