SQLite

//
%ifndef SQLITE_OMIT_WINDOWFUNC
%type windowdefn_list {Window*}
%destructor windowdefn_list {sqlite3WindowListDelete(pParse->db, $$);}
windowdefn_list(A) ::= windowdefn(Z). { A = Z; }
windowdefn_list(A) ::= windowdefn_list(Y) COMMA windowdefn(Z). {
  assert( Z!=0 );
  sqlite3WindowChain(pParse, Z, Y);
  Z->pNextWin = Y;
  A = Z;
}

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

%type window {Window*}

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

window(A) ::= PARTITION BY nexprlist(X) orderby_opt(Y) frame_opt(Z). {
  A = sqlite3WindowAssemble(pParse, Z, X, Y, 0);

}
window(A) ::= nm(W) PARTITION BY nexprlist(X) orderby_opt(Y) frame_opt(Z). {
  A = sqlite3WindowAssemble(pParse, Z, X, Y, &W);
}
window(A) ::= ORDER BY sortlist(Y) frame_opt(Z). {
  A = sqlite3WindowAssemble(pParse, Z, 0, Y, 0);
}
window(A) ::= nm(W) ORDER BY sortlist(Y) frame_opt(Z). {
  A = sqlite3WindowAssemble(pParse, Z, 0, Y, &W);
}
window(A) ::= frame_opt(Z). {
  A = Z;
}
window(A) ::= nm(W) frame_opt(Z). {
  A = sqlite3WindowAssemble(pParse, Z, 0, 0, &W);
}

frame_opt(A) ::= .                             { 
  A = sqlite3WindowAlloc(pParse, 0, TK_UNBOUNDED, 0, TK_CURRENT, 0);
}
frame_opt(A) ::= range_or_rows(X) frame_bound_s(Y). { 
  A = sqlite3WindowAlloc(pParse, X, Y.eType, Y.pExpr, TK_CURRENT, 0);
}
frame_opt(A) ::= range_or_rows(X) BETWEEN frame_bound_s(Y) AND frame_bound_e(Z). { 
  A = sqlite3WindowAlloc(pParse, X, Y.eType, Y.pExpr, Z.eType, Z.pExpr);
}

%type window_clause {Window*}
%destructor window_clause {sqlite3WindowListDelete(pParse->db, $$);}
window_clause(A) ::= WINDOW windowdefn_list(B). { A = B; }

%type over_clause {Window*}
%destructor over_clause {sqlite3WindowDelete(pParse->db, $$);}
over_clause(A) ::= filter_opt(W) OVER LP window(Z) RP. {
  A = Z;
  assert( A!=0 );
  A->pFilter = W;
}
over_clause(A) ::= filter_opt(W) OVER nm(Z). {
  A = (Window*)sqlite3DbMallocZero(pParse->db, sizeof(Window));
  if( A ){

**       object on a linked list attached to Select.pWinDefn.
**
** The uses (1) and (2) are really the same Window object that just happens
** to be accessible in two different ways.  Use (3) is are separate objects.
*/
struct Window {
  char *zName;            /* Name of window (may be NULL) */
  char *zBase;            /* Name of base window for chaining (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 */
  u8 bImplicitFrame;      /* True if frame was implicitly specified */
  Expr *pStart;           /* Expression for "<expr> PRECEDING" */
  Expr *pEnd;             /* Expression for "<expr> FOLLOWING" */
  Window *pNextWin;       /* Next window function belonging to this SELECT */
  Expr *pFilter;          /* The FILTER expression */
  FuncDef *pFunc;         /* The function */
  int iEphCsr;            /* Partition buffer or Peer buffer */
  int regAccum;

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, Expr *pOwner, Window *p);
Window *sqlite3WindowListDup(sqlite3 *db, Window *p);
void sqlite3WindowFunctions(void);
void sqlite3WindowChain(Parse*, Window*, Window*);
Window *sqlite3WindowAssemble(Parse*, Window*, ExprList*, ExprList*, Token*);
#else
# define sqlite3WindowDelete(a,b)
# define sqlite3WindowFunctions()
# define sqlite3WindowAttach(a,b,c)
#endif

/*

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

static Window *windowFind(Parse *pParse, Window *pList, const char *zName){
  Window *p;
  for(p=pList; p; p=p->pNextWin){
    if( sqlite3StrICmp(p->zName, zName)==0 ) break;
  }
  if( p==0 ){
    sqlite3ErrorMsg(pParse, "no such window: %s", zName);
  }
  return p;
}

/*
** This function is called immediately after resolving the function name
** for a window function within a SELECT statement. Argument pList is a
** linked list of WINDOW definitions for the current SELECT statement.
** Argument pFunc is the function definition just resolved and pWin
** is the Window object representing the associated OVER clause. This

void sqlite3WindowUpdate(
  Parse *pParse, 
  Window *pList,                  /* List of named windows for this SELECT */
  Window *pWin,                   /* Window frame to update */
  FuncDef *pFunc                  /* Window function definition */
){
  if( pWin->zName && pWin->eType==0 ){
    Window *p = windowFind(pParse, pList, pWin->zName);



    if( p==0 ) 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;
    pWin->eType = p->eType;
  }else{
    sqlite3WindowChain(pParse, pWin, pList);
  }
  if( pFunc->funcFlags & SQLITE_FUNC_WINDOW ){
    sqlite3 *db = pParse->db;
    if( pWin->pFilter ){
      sqlite3ErrorMsg(pParse, 
          "FILTER clause may only be used with aggregate window functions"
      );

  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->zBase);
    sqlite3DbFree(db, p);
  }
}

/*
** Free the linked list of Window objects starting at the second argument.
*/

  int eType,        /* Frame type. TK_RANGE or TK_ROWS */
  int eStart,       /* Start type: CURRENT, PRECEDING, FOLLOWING, UNBOUNDED */
  Expr *pStart,     /* Start window size if TK_PRECEDING or FOLLOWING */
  int eEnd,         /* End type: CURRENT, FOLLOWING, TK_UNBOUNDED, PRECEDING */
  Expr *pEnd        /* End window size if TK_FOLLOWING or PRECEDING */
){
  Window *pWin = 0;
  int bImplicitFrame = 0;

  /* Parser assures the following: */
  assert( eType==0 || eType==TK_RANGE || eType==TK_ROWS );
  assert( eStart==TK_CURRENT || eStart==TK_PRECEDING
           || eStart==TK_UNBOUNDED || eStart==TK_FOLLOWING );
  assert( eEnd==TK_CURRENT || eEnd==TK_FOLLOWING
           || eEnd==TK_UNBOUNDED || eEnd==TK_PRECEDING );
  assert( (eStart==TK_PRECEDING || eStart==TK_FOLLOWING)==(pStart!=0) );
  assert( (eEnd==TK_FOLLOWING || eEnd==TK_PRECEDING)==(pEnd!=0) );

  if( eType==0 ){
    bImplicitFrame = 1;
    eType = TK_RANGE;
  }

  /* If a frame is declared "RANGE" (not "ROWS"), then it may not use
  ** either "<expr> PRECEDING" or "<expr> FOLLOWING".
  */
  if( eType==TK_RANGE && (pStart!=0 || pEnd!=0) ){
    sqlite3ErrorMsg(pParse, "RANGE must use only UNBOUNDED or CURRENT ROW");
    goto windowAllocErr;

  }

  pWin = (Window*)sqlite3DbMallocZero(pParse->db, sizeof(Window));
  if( pWin==0 ) goto windowAllocErr;
  pWin->eType = eType;
  pWin->eStart = eStart;
  pWin->eEnd = eEnd;
  pWin->bImplicitFrame = bImplicitFrame;
  pWin->pEnd = sqlite3WindowOffsetExpr(pParse, pEnd);
  pWin->pStart = sqlite3WindowOffsetExpr(pParse, pStart);
  return pWin;

windowAllocErr:
  sqlite3ExprDelete(pParse->db, pEnd);
  sqlite3ExprDelete(pParse->db, pStart);
  return 0;
}

/*
** Attach PARTITION and ORDER BY clauses pPartition and pOrderBy to window
** pWin. Also, if parameter pBase is not NULL, set pWin->zBase to the
** equivalent nul-terminated string.
*/
Window *sqlite3WindowAssemble(
  Parse *pParse, 
  Window *pWin, 
  ExprList *pPartition, 
  ExprList *pOrderBy, 
  Token *pBase
){
  if( pWin ){
    pWin->pPartition = pPartition;
    pWin->pOrderBy = pOrderBy;
    if( pBase ){
      pWin->zBase = sqlite3DbStrNDup(pParse->db, pBase->z, pBase->n);
    }
  }else{
    sqlite3ExprListDelete(pParse->db, pPartition);
    sqlite3ExprListDelete(pParse->db, pOrderBy);
  }
  return pWin;
}

/*
** Window *pWin has just been created from a WINDOW clause. Tokne pBase
** is the base window. Earlier windows from the same WINDOW clause are
** stored in the linked list starting at pWin->pNextWin. This function
** either updates *pWin according to the base specification, or else
** leaves an error in pParse.
*/
void sqlite3WindowChain(Parse *pParse, Window *pWin, Window *pList){
  if( pWin->zBase ){
    sqlite3 *db = pParse->db;
    Window *pExist = windowFind(pParse, pList, pWin->zBase);
    if( pExist ){
      const char *zErr = 0;
      /* Check for errors */
      if( pWin->pPartition ){
        zErr = "PARTITION clause";
      }else if( pExist->pOrderBy && pWin->pOrderBy ){
        zErr = "ORDER BY clause";
      }else if( pExist->bImplicitFrame==0 ){
        zErr = "frame specification";
      }
      if( zErr ){
        sqlite3ErrorMsg(pParse, 
            "cannot override %s of window: %s", zErr, pWin->zBase
        );
      }else{
        pWin->pPartition = sqlite3ExprListDup(db, pExist->pPartition, 0);
        if( pExist->pOrderBy ){
          assert( pWin->pOrderBy==0 );
          pWin->pOrderBy = sqlite3ExprListDup(db, pExist->pOrderBy, 0);
        }
        sqlite3DbFree(db, pWin->zBase);
        pWin->zBase = 0;
      }
    }
  }
}

/*
** Attach window object pWin to expression p.
*/
void sqlite3WindowAttach(Parse *pParse, Expr *p, Window *pWin){
  if( p ){
    assert( p->op==TK_FUNCTION );

  WINDOW w1 AS (PARTITION BY b IN (SELECT rowid FROM t7));
} {
  2 10
  1 101
  3 101
}

#-------------------------------------------------------------------------
# Test error cases from chaining window definitions.
#
reset_db
do_execsql_test 17.0 {
  DROP TABLE IF EXISTS t1;
  CREATE TABLE t1(a INTEGER PRIMARY KEY, b TEXT, c TEXT, d INTEGER);
  INSERT INTO t1 VALUES(1, 'odd',  'one',   1);
  INSERT INTO t1 VALUES(2, 'even', 'two',   2);
  INSERT INTO t1 VALUES(3, 'odd',  'three', 3);
  INSERT INTO t1 VALUES(4, 'even', 'four',  4);
  INSERT INTO t1 VALUES(5, 'odd',  'five',  5);
  INSERT INTO t1 VALUES(6, 'even', 'six',   6);
}

foreach {tn sql error} {
  1 {
    SELECT c, sum(d) OVER win2 FROM t1
      WINDOW win1 AS (ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING), 
             win2 AS (win1 ORDER BY b)
  } {cannot override frame specification of window: win1}

  2 {
    SELECT c, sum(d) OVER win2 FROM t1
      WINDOW win1 AS (),
             win2 AS (win4 ORDER BY b)
  } {no such window: win4}

  3 {
    SELECT c, sum(d) OVER win2 FROM t1
      WINDOW win1 AS (),
             win2 AS (win1 PARTITION BY d)
  } {cannot override PARTITION clause of window: win1}

  4 {
    SELECT c, sum(d) OVER win2 FROM t1
      WINDOW win1 AS (ORDER BY b),
             win2 AS (win1 ORDER BY d)
  } {cannot override ORDER BY clause of window: win1}
} {
  do_catchsql_test 17.1.$tn $sql [list 1 $error]
}

foreach {tn sql error} {
  1 {
    SELECT c, sum(d) OVER (win1 ORDER BY b) FROM t1
      WINDOW win1 AS (ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING)
  } {cannot override frame specification of window: win1}

  2 {
    SELECT c, sum(d) OVER (win4 ORDER BY b) FROM t1
      WINDOW win1 AS ()
  } {no such window: win4}

  3 {
    SELECT c, sum(d) OVER (win1 PARTITION BY d) FROM t1
      WINDOW win1 AS ()
  } {cannot override PARTITION clause of window: win1}

  4 {
    SELECT c, sum(d) OVER (win1 ORDER BY d) FROM t1
      WINDOW win1 AS (ORDER BY b)
  } {cannot override ORDER BY clause of window: win1}
} {
  do_catchsql_test 17.2.$tn $sql [list 1 $error]
}

do_execsql_test 17.3.1 {
  SELECT group_concat(c, '.') OVER (PARTITION BY b ORDER BY c)
  FROM t1
} {four four.six four.six.two five five.one five.one.three}

do_execsql_test 17.3.2 {
  SELECT group_concat(c, '.') OVER (win1 ORDER BY c)
  FROM t1
  WINDOW win1 AS (PARTITION BY b)
} {four four.six four.six.two five five.one five.one.three}

do_execsql_test 17.3.3 {
  SELECT group_concat(c, '.') OVER win2
  FROM t1
  WINDOW win1 AS (PARTITION BY b),
         win2 AS (win1 ORDER BY c)
} {four four.six four.six.two five five.one five.one.three}

do_execsql_test 17.3.4 {
  SELECT group_concat(c, '.') OVER (win2)
  FROM t1
  WINDOW win1 AS (PARTITION BY b),
         win2 AS (win1 ORDER BY c)
} {four four.six four.six.two five five.one five.one.three}

do_execsql_test 17.3.5 {
  SELECT group_concat(c, '.') OVER win5
  FROM t1
  WINDOW win1 AS (PARTITION BY b),
         win2 AS (win1),
         win3 AS (win2),
         win4 AS (win3),
         win5 AS (win4 ORDER BY c)
} {four four.six four.six.two five five.one five.one.three}

finish_test

start_test window3 "2018 May 31"
ifcapable !windowfunc

execsql_test 1.0 {
  DROP TABLE IF EXISTS t2;
  CREATE TABLE t2(a INTEGER PRIMARY KEY, b INTEGER);
  INSERT INTO t2(a, b) VALUES

  (10,89), (11,81), (12,96), (13,59), (14,38), (15,68), (16,39), (17,62),
  (18,91), (19,46), (20,6), (21,99), (22,97), (23,27), (24,46), (25,78),
  (26,54), (27,97), (28,8), (29,67), (30,29), (31,93), (32,84), (33,77),
  (34,23), (35,16), (36,16), (37,93), (38,65), (39,35), (40,47), (41,7),
  (42,86), (43,74), (44,61), (45,91), (46,85), (47,24), (48,85), (49,43),
  (50,59), (51,12), (52,32), (53,56), (54,3), (55,91), (56,22), (57,90),
  (58,55), (59,15), (60,28), (61,89), (62,25), (63,47), (64,1), (65,56),

  "
  execsql_test 1.$tn.14.5 "
    SELECT string_agg(CAST(b AS TEXT), '.') OVER ( ORDER BY b%10,a $window ) FROM t2
  "
  execsql_test 1.$tn.14.6 "
    SELECT string_agg(CAST(b AS TEXT), '.') OVER (PARTITION BY b%2,a ORDER BY b%10 $window) FROM t2
  "

  execsql_test 1.$tn.14.7 "
    SELECT string_agg(CAST(b AS TEXT), '.') OVER (win1 ORDER BY b%10 $window) 
    FROM t2
    WINDOW win1 AS (PARTITION BY b%2,a)
    ORDER BY 1
  "

  execsql_test 1.$tn.14.8 "
    SELECT string_agg(CAST(b AS TEXT), '.') OVER (win1 $window) 
    FROM t2
    WINDOW win1 AS (PARTITION BY b%2,a ORDER BY b%10)
    ORDER BY 1
  "

  execsql_test 1.$tn.14.9 "
    SELECT string_agg(CAST(b AS TEXT), '.') OVER win2
    FROM t2
    WINDOW win1 AS (PARTITION BY b%2,a ORDER BY b%10),
           win2 AS (win1 $window)
    ORDER BY 1
  "

  execsql_test 1.$tn.15.1 "
    SELECT count(*) OVER win, string_agg(CAST(b AS TEXT), '.') 
    FILTER (WHERE a%2=0) OVER win FROM t2
    WINDOW win AS (ORDER BY a $window)
  "