SQLite

    pNew->iOffset = 0;
    pNew->selFlags = p->selFlags & ~SF_UsesEphemeral;
    pNew->addrOpenEphm[0] = -1;
    pNew->addrOpenEphm[1] = -1;
    pNew->nSelectRow = p->nSelectRow;
    pNew->pWith = withDup(db, p->pWith);
    pNew->pWin = 0;
    pNew->pWinDefn = 0;           /* TODO!! */
    sqlite3SelectSetName(pNew, p->zSelName);
    *pp = pNew;
    pp = &pNew->pPrior;
    pNext = pNew;
  }

  return pRet;

  int nVal, nSep;
  assert( argc==1 || argc==2 );
  if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
  pAccum = (StrAccum*)sqlite3_aggregate_context(context, sizeof(*pAccum));

  if( pAccum ){
    sqlite3 *db = sqlite3_context_db_handle(context);
    int firstTerm = pAccum->mxAlloc==0;
    pAccum->mxAlloc = db->aLimit[SQLITE_LIMIT_LENGTH];
    if( !firstTerm ){
      if( argc==2 ){
        zSep = (char*)sqlite3_value_text(argv[1]);
        nSep = sqlite3_value_bytes(argv[1]);
      }else{
        zSep = ",";

    }
    if( n>=pAccum->nChar ){
      pAccum->nChar = 0;
    }else{
      pAccum->nChar -= n;
      memmove(pAccum->zText, &pAccum->zText[n], pAccum->nChar);
    }
    if( pAccum->nChar==0 ) pAccum->mxAlloc = 0;
  }
}
static void groupConcatFinalize(sqlite3_context *context){
  StrAccum *pAccum;
  pAccum = sqlite3_aggregate_context(context, 0);
  if( pAccum ){
    if( pAccum->accError==SQLITE_TOOBIG ){

}
%type multiselect_op {int}
multiselect_op(A) ::= UNION(OP).             {A = @OP; /*A-overwrites-OP*/}
multiselect_op(A) ::= UNION ALL.             {A = TK_ALL;}
multiselect_op(A) ::= EXCEPT|INTERSECT(OP).  {A = @OP; /*A-overwrites-OP*/}
%endif SQLITE_OMIT_COMPOUND_SELECT
oneselect(A) ::= SELECT(S) distinct(D) selcollist(W) from(X) where_opt(Y)
                 groupby_opt(P) having_opt(Q) windowdefn_opt(R)
                 orderby_opt(Z) limit_opt(L). {
#if SELECTTRACE_ENABLED
  Token s = S; /*A-overwrites-S*/
#endif
  A = sqlite3SelectNew(pParse,W,X,Y,P,Q,Z,D,L);
  if( A ) A->pWinDefn = R;
#if SELECTTRACE_ENABLED
  /* Populate the Select.zSelName[] string that is used to help with
  ** query planner debugging, to differentiate between multiple Select
  ** objects in a complex query.
  **
  ** If the SELECT keyword is immediately followed by a C-style comment
  ** then extract the first few alphanumeric characters from within that

}
%ifndef SQLITE_OMIT_CAST
expr(A) ::= CAST LP expr(E) AS typetoken(T) RP. {
  A = sqlite3ExprAlloc(pParse->db, TK_CAST, &T, 1);
  sqlite3ExprAttachSubtrees(pParse->db, A, E, 0);
}
%endif  SQLITE_OMIT_CAST
expr(A) ::= id(X) LP distinct(D) exprlist(Y) RP over_opt(Z). {
  if( Y && Y->nExpr>pParse->db->aLimit[SQLITE_LIMIT_FUNCTION_ARG] ){
    sqlite3ErrorMsg(pParse, "too many arguments on function %T", &X);
  }
  A = sqlite3ExprFunction(pParse, Y, &X);
  sqlite3WindowAttach(pParse, A, Z);
  if( D==SF_Distinct && A ){
    A->flags |= EP_Distinct;
  }
}
expr(A) ::= id(X) LP STAR RP over_opt(Z). {
  A = sqlite3ExprFunction(pParse, 0, &X);
  sqlite3WindowAttach(pParse, A, Z);
}
term(A) ::= CTIME_KW(OP). {
  A = sqlite3ExprFunction(pParse, 0, &OP);
}

%type windowdefn_opt {Window*}
%destructor windowdefn_opt {sqlite3WindowDelete(pParse->db, $$);}
windowdefn_opt(A) ::= . { A = 0; }
windowdefn_opt(A) ::= WINDOW windowdefn_list(B). { A = B; }

%type windowdefn_list {Window*}
%destructor windowdefn_list {sqlite3WindowDelete(pParse->db, $$);}
windowdefn_list(A) ::= windowdefn(Z). { A = Z; }
windowdefn_list(A) ::= windowdefn_list(Y) COMMA windowdefn(Z). {
  if( Z ) Z->pNextWin = Y;
  A = Z;
}

%type windowdefn {Window*}
%destructor windowdefn {sqlite3WindowDelete(pParse->db, $$);}
windowdefn(A) ::= nm(X) AS window(Y). {
  if( Y ){
    Y->zName = sqlite3DbStrNDup(pParse->db, X.z, X.n);
  }
  A = Y;
}

%type over_opt {Window*}
%destructor over_opt {sqlite3WindowDelete(pParse->db, $$);}

%type window {Window*}
%destructor window {sqlite3WindowDelete(pParse->db, $$);}

%type frame_opt {Window*}
%destructor frame_opt {sqlite3WindowDelete(pParse->db, $$);}

%type window_or_nm {Window*}
%destructor window_or_nm {
sqlite3WindowDelete(pParse->db, $$);}

%type part_opt {ExprList*}
%destructor part_opt {sqlite3ExprListDelete(pParse->db, $$);}

%type filter_opt {Expr*}
%destructor filter_opt {sqlite3ExprDelete(pParse->db, $$);}

%type range_or_rows {int}

%type frame_bound {struct FrameBound}
%destructor frame_bound {sqlite3ExprDelete(pParse->db, $$.pExpr);}

over_opt(A) ::= . { A = 0; }
over_opt(A) ::= filter_opt(W) OVER window_or_nm(Z). {

  A = Z;
  if( A ) A->pFilter = W;
}

window_or_nm(A) ::= window(Z). {A = Z;}
window_or_nm(A) ::= nm(Z). {
  A = (Window*)sqlite3DbMallocZero(pParse->db, sizeof(Window));
  if( A ){
    A->zName = sqlite3DbStrNDup(pParse->db, Z.z, Z.n);
  }
}

window(A) ::= LP part_opt(X) orderby_opt(Y) frame_opt(Z) RP. {
  A = Z;
  if( A ){
    A->pPartition = X;
    A->pOrderBy = Y;
  }
}

part_opt(A) ::= PARTITION BY exprlist(X). { A = X; }
part_opt(A) ::= .                         { A = 0; }

             nId, zId);
        pNC->nErr++;
      }
      if( is_agg ) pNC->ncFlags &= ~NC_AllowAgg;
      sqlite3WalkExprList(pWalker, pList);
      if( is_agg ){
        if( pExpr->pWin ){
          Select *pSel = pNC->pWinSelect;
          sqlite3WindowUpdate(pParse, pSel->pWinDefn, pExpr->pWin, pDef);
          if( 0==pSel->pWin 
           || 0==sqlite3WindowCompare(pParse, pSel->pWin, pExpr->pWin) 
          ){
            pExpr->pWin->pNextWin = pSel->pWin;
            pSel->pWin = pExpr->pWin;
          }
          pExpr->pWin->pFunc = pDef;
          pExpr->pWin->nArg = (pExpr->x.pList ? pExpr->x.pList->nExpr : 0);
        }else{
          NameContext *pNC2 = pNC;
          pExpr->op = TK_AGG_FUNCTION;
          pExpr->op2 = 0;

    p->selFlags |= SF_Resolved;

    /* Resolve the expressions in the LIMIT and OFFSET clauses. These
    ** are not allowed to refer to any names, so pass an empty NameContext.
    */
    memset(&sNC, 0, sizeof(sNC));
    sNC.pParse = pParse;
    sNC.pWinSelect = p;
    if( sqlite3ResolveExprNames(&sNC, p->pLimit) ){
      return WRC_Abort;
    }

    /* If the SF_Converted flags is set, then this Select object was
    ** was created by the convertCompoundSelectToSubquery() function.
    ** In this case the ORDER BY clause (p->pOrderBy) should be resolved

    /* If this is part of a compound SELECT, check that it has the right
    ** number of expressions in the select list. */
    if( p->pNext && p->pEList->nExpr!=p->pNext->pEList->nExpr ){
      sqlite3SelectWrongNumTermsError(pParse, p->pNext);
      return WRC_Abort;
    }




    /* Advance to the next term of the compound
    */
    p = p->pPrior;
    nCompound++;
  }

  /* Resolve the ORDER BY on a compound SELECT after all terms of

    sqlite3ExprListDelete(db, p->pEList);
    sqlite3SrcListDelete(db, p->pSrc);
    sqlite3ExprDelete(db, p->pWhere);
    sqlite3ExprListDelete(db, p->pGroupBy);
    sqlite3ExprDelete(db, p->pHaving);
    sqlite3ExprListDelete(db, p->pOrderBy);
    sqlite3ExprDelete(db, p->pLimit);
    if( OK_IF_ALWAYS_TRUE(p->pWinDefn) ){
      sqlite3WindowListDelete(db, p->pWinDefn);
    }
    if( OK_IF_ALWAYS_TRUE(p->pWith) ) sqlite3WithDelete(db, p->pWith);
    if( bFree ) sqlite3DbFreeNN(db, p);
    p = pPrior;
    bFree = 1;
  }
}

  pNew->pHaving = pHaving;
  pNew->pOrderBy = pOrderBy;
  pNew->pPrior = 0;
  pNew->pNext = 0;
  pNew->pLimit = pLimit;
  pNew->pWith = 0;
  pNew->pWin = 0;
  pNew->pWinDefn = 0;
  if( pParse->db->mallocFailed ) {
    clearSelect(pParse->db, pNew, pNew!=&standin);
    pNew = 0;
  }else{
    assert( pNew->pSrc!=0 || pParse->nErr>0 );
  }
  assert( pNew!=&standin );

    AggInfo *pAggInfo;   /* Information about aggregates at this level */
    Upsert *pUpsert;     /* ON CONFLICT clause information from an upsert */
  } uNC;
  NameContext *pNext;  /* Next outer name context.  NULL for outermost */
  int nRef;            /* Number of names resolved by this context */
  int nErr;            /* Number of errors encountered while resolving names */
  u16 ncFlags;         /* Zero or more NC_* flags defined below */
  Select *pWinSelect;  /* SELECT statement for any window functions */
};

/*
** Allowed values for the NameContext, ncFlags field.
**
** Value constraints (all checked via assert()):
**    NC_HasAgg    == SF_HasAgg

  Expr *pHaving;         /* The HAVING clause */
  ExprList *pOrderBy;    /* The ORDER BY clause */
  Select *pPrior;        /* Prior select in a compound select statement */
  Select *pNext;         /* Next select to the left in a compound */
  Expr *pLimit;          /* LIMIT expression. NULL means not used. */
  With *pWith;           /* WITH clause attached to this select. Or NULL. */
  Window *pWin;          /* List of window functions */
  Window *pWinDefn;      /* List of named window definitions */
};

/*
** Allowed values for Select.selFlags.  The "SF" prefix stands for
** "Select Flag".
**
** Value constraints (all checked via assert())

struct TreeView {
  int iLevel;             /* Which level of the tree we are on */
  u8  bLine[100];         /* Draw vertical in column i if bLine[i] is true */
};
#endif /* SQLITE_DEBUG */

struct Window {
  char *zName;            /* Name of window (may be NULL) */
  ExprList *pPartition;   /* PARTITION BY clause */
  ExprList *pOrderBy;     /* ORDER BY clause */
  u8 eType;               /* TK_RANGE or TK_ROWS */
  u8 eStart;              /* UNBOUNDED, CURRENT, PRECEDING or FOLLOWING */
  u8 eEnd;                /* UNBOUNDED, CURRENT, PRECEDING or FOLLOWING */
  Expr *pStart;           /* Expression for "<expr> PRECEDING" */
  Expr *pEnd;             /* Expression for "<expr> FOLLOWING" */

  Window *pNextWin;       /* Next window function belonging to this SELECT */

  Expr *pFilter;
  FuncDef *pFunc;
  int nArg;

  int iEphCsr;            /* Temp table used by this window */
  int regAccum;
  int regResult;

  int csrApp;             /* Function cursor (used by min/max) */
  int regApp;             /* Function register (also used by min/max) */

  int regPart;
  Expr *pOwner;           /* Expression object this window is attached to */
  int nBufferCol;         /* Number of columns in buffer table */
  int iArgCol;            /* Offset of first argument for this function */
};

void sqlite3WindowDelete(sqlite3*, Window*);
void sqlite3WindowListDelete(sqlite3 *db, Window *p);
Window *sqlite3WindowAlloc(Parse*, int, int, Expr*, int , Expr*);
void sqlite3WindowAttach(Parse*, Expr*, Window*);
int sqlite3WindowCompare(Parse*, Window*, Window*);
void sqlite3WindowCodeInit(Parse*, Window*);
void sqlite3WindowCodeStep(Parse*, Select*, WhereInfo*, int, int);
int sqlite3WindowRewrite(Parse*, Select*);
int sqlite3ExpandSubquery(Parse*, struct SrcList_item*);
void sqlite3WindowUpdate(Parse*, Window*, Window*, FuncDef*);
Window *sqlite3WindowDup(sqlite3 *db, Window *p);

/*
** Assuming zIn points to the first byte of a UTF-8 character,
** advance zIn to point to the first byte of the next UTF-8 character.
*/
#define SQLITE_SKIP_UTF8(zIn) {                        \

    WINDOWFUNC(first_value, 1, 0),
    WINDOWFUNC(lead, 1, 0), WINDOWFUNC(lead, 2, 0), WINDOWFUNC(lead, 3, 0),
    WINDOWFUNC(lag, 1, 0),  WINDOWFUNC(lag, 2, 0),  WINDOWFUNC(lag, 3, 0),
  };
  sqlite3InsertBuiltinFuncs(aWindowFuncs, ArraySize(aWindowFuncs));
}

void sqlite3WindowUpdate(
  Parse *pParse, 
  Window *pList, 
  Window *pWin, 
  FuncDef *pFunc
){
  if( pWin->zName ){
    Window *p;
    for(p=pList; p; p=p->pNextWin){
      if( sqlite3StrICmp(p->zName, pWin->zName)==0 ) break;
    }
    if( p==0 ){
      sqlite3ErrorMsg(pParse, "no such window: %s", pWin->zName);
      return;
    }
    pWin->pPartition = sqlite3ExprListDup(pParse->db, p->pPartition, 0);
    pWin->pOrderBy = sqlite3ExprListDup(pParse->db, p->pOrderBy, 0);
    pWin->pStart = sqlite3ExprDup(pParse->db, p->pStart, 0);
    pWin->pEnd = sqlite3ExprDup(pParse->db, p->pEnd, 0);
    pWin->eStart = p->eStart;
    pWin->eEnd = p->eEnd;
  }
  if( pFunc->funcFlags & SQLITE_FUNC_WINDOW ){
    sqlite3 *db = pParse->db;
    if( pFunc->xSFunc==row_numberStepFunc || pFunc->xSFunc==ntileStepFunc ){
      sqlite3ExprDelete(db, pWin->pStart);
      sqlite3ExprDelete(db, pWin->pEnd);
      pWin->pStart = pWin->pEnd = 0;
      pWin->eType = TK_ROWS;

void sqlite3WindowDelete(sqlite3 *db, Window *p){
  if( p ){
    sqlite3ExprDelete(db, p->pFilter);
    sqlite3ExprListDelete(db, p->pPartition);
    sqlite3ExprListDelete(db, p->pOrderBy);
    sqlite3ExprDelete(db, p->pEnd);
    sqlite3ExprDelete(db, p->pStart);
    sqlite3DbFree(db, p->zName);
    sqlite3DbFree(db, p);
  }
}

void sqlite3WindowListDelete(sqlite3 *db, Window *p){
  while( p ){
    Window *pNext = p->pNextWin;
    sqlite3WindowDelete(db, p);
    p = pNext;
  }
}

Window *sqlite3WindowAlloc(
  Parse *pParse, 
  int eType,
  int eStart, Expr *pStart,
  int eEnd, Expr *pEnd
){

execsql_test 3.1 {
  SELECT a, nth_value(c, d) OVER (ORDER BY b) FROM t5
}

execsql_test 3.2 {
  SELECT a, nth_value(c, d) OVER (PARTITION BY b ORDER BY a) FROM t5
}

execsql_test 3.3 {
  SELECT a, count(*) OVER abc, count(*) OVER def FROM t5
  WINDOW abc AS (ORDER BY a), 
         def AS (ORDER BY a DESC)
  ORDER BY a;
}

finish_test

  SELECT a, nth_value(c, d) OVER (ORDER BY b) FROM t5
} {1 {}   3 five   5 one   2 two   4 three}

do_execsql_test 3.2 {
  SELECT a, nth_value(c, d) OVER (PARTITION BY b ORDER BY a) FROM t5
} {1 {}   3 {}   5 one   2 {}   4 four}

do_execsql_test 3.3 {
  SELECT a, count(*) OVER abc, count(*) OVER def FROM t5
  WINDOW abc AS (ORDER BY a), 
         def AS (ORDER BY a DESC)
  ORDER BY a;
} {1 1 5   2 2 4   3 3 3   4 4 2   5 5 1}

finish_test

  { "UNIQUE",           "TK_UNIQUE",       ALWAYS                 },
  { "UPDATE",           "TK_UPDATE",       ALWAYS                 },
  { "USING",            "TK_USING",        ALWAYS                 },
  { "VACUUM",           "TK_VACUUM",       VACUUM                 },
  { "VALUES",           "TK_VALUES",       ALWAYS                 },
  { "VIEW",             "TK_VIEW",         VIEW                   },
  { "VIRTUAL",          "TK_VIRTUAL",      VTAB                   },
  { "WINDOW",           "TK_WINDOW",       ALWAYS                 },
  { "WITH",             "TK_WITH",         CTE                    },
  { "WITHOUT",          "TK_WITHOUT",      ALWAYS                 },
  { "WHEN",             "TK_WHEN",         ALWAYS                 },
  { "WHERE",            "TK_WHERE",        ALWAYS                 },
};

/* Number of keywords */