SQLite

          /* Date/time functions that use 'now', and other functions like
          ** sqlite_version() that might change over time cannot be used
          ** in an index. */
          notValid(pParse, pNC, "non-deterministic functions",
                   NC_IdxExpr|NC_PartIdx);
        }
      }

      if( is_agg==0 && pExpr->pWin ){
        sqlite3ErrorMsg(pParse, 
            "%.*s() may not be used as a window function", nId, zId
        );
        pNC->nErr++;
      }else if( 
            (is_agg && (pNC->ncFlags & NC_AllowAgg)==0)
         || (is_agg && (pDef->funcFlags & SQLITE_FUNC_WINDOW) && !pExpr->pWin)
         || (is_agg && pExpr->pWin && (pNC->ncFlags & NC_AllowWin)==0)
      ){
        const char *zType;
        if( (pDef->funcFlags & SQLITE_FUNC_WINDOW) || pExpr->pWin ){
          zType = "window";
        }else{
          zType = "aggregate";
        }
        sqlite3ErrorMsg(pParse, "misuse of %s function %.*s()", zType, nId,zId);
        pNC->nErr++;
        is_agg = 0;
      }else if( no_such_func && pParse->db->init.busy==0
#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
                && pParse->explain==0
#endif
      ){

/*
** 2018 May 08
**
** 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.

  if( pMWin->pEnd ){
    sqlite3ExprCode(pParse, pMWin->pEnd, regEnd);
    windowCheckFrameValue(pParse, regEnd, 1);
  }

  /* If this is "ROWS <expr1> FOLLOWING AND ROWS <expr2> FOLLOWING", do:
  **
  **   if( regEnd<regStart ){
  **     // The frame always consists of 0 rows
  **     regStart = regSize;
  **   }
  **   regEnd = regEnd - regStart;
  */
  if( pMWin->pEnd && pMWin->pStart && pMWin->eStart==TK_FOLLOWING ){
    assert( pMWin->eEnd==TK_FOLLOWING );
    sqlite3VdbeAddOp3(v, OP_Ge, regStart, sqlite3VdbeCurrentAddr(v)+2, regEnd);
    sqlite3VdbeAddOp2(v, OP_Copy, regSize, regStart);
    sqlite3VdbeAddOp3(v, OP_Subtract, regStart, regEnd, regEnd);
  }

  if( pMWin->pEnd && pMWin->pStart && pMWin->eEnd==TK_PRECEDING ){
    assert( pMWin->eStart==TK_PRECEDING );
    sqlite3VdbeAddOp3(v, OP_Le, regStart, sqlite3VdbeCurrentAddr(v)+3, regEnd);
    sqlite3VdbeAddOp2(v, OP_Copy, regSize, regStart);
    sqlite3VdbeAddOp2(v, OP_Copy, regSize, regEnd);
  }

  /* Initialize the accumulator register for each window function to NULL */
  regArg = windowInitAccum(pParse, pMWin);

  sqlite3VdbeAddOp2(v, OP_Rewind, pMWin->iEphCsr, lblFlushDone);
  sqlite3VdbeAddOp2(v, OP_Rewind, csrStart, lblFlushDone);
  sqlite3VdbeChangeP5(v, 1);

  WhereInfo *pWInfo,
  int regGosub, 
  int addrGosub
){
  Window *pMWin = p->pWin;
  Window *pWin;

  /*
  ** Call windowCodeRowExprStep() for all window modes *except*:
  **
  **   RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
  **   RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
  **   RANGE BETWEEN CURRENT ROW AND CURRENT ROW
  **   ROWS  BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
  */
  if( (pMWin->eType==TK_ROWS 
   && (pMWin->eStart!=TK_UNBOUNDED||pMWin->eEnd!=TK_CURRENT||!pMWin->pOrderBy))
   || (pMWin->eStart==TK_CURRENT&&pMWin->eEnd==TK_UNBOUNDED&&pMWin->pOrderBy)
  ){
    windowCodeRowExprStep(pParse, p, pWInfo, regGosub, addrGosub);
    return;
  }

  /*
  ** Call windowCodeCacheStep() if there is a window function that requires
  ** that the entire partition be cached in a temp table before any rows
  ** are returned.
  */
  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
    FuncDef *pFunc = pWin->pFunc;
    if( (pFunc->funcFlags & SQLITE_FUNC_WINDOW_SIZE)
     || (pFunc->xSFunc==nth_valueStepFunc)
     || (pFunc->xSFunc==first_valueStepFunc)
     || (pFunc->xSFunc==leadStepFunc)
     || (pFunc->xSFunc==lagStepFunc)

do_execsql_test 6.2 {
  SELECT * FROM t2, (SELECT x, count(*) OVER (ORDER BY x) FROM t1);
} {
  b 1 1 b 2 2 b 3 3 b 4 4 b 5 5 b 6 6 b 7 7
  a 1 1 a 2 2 a 3 3 a 4 4 a 5 5 a 6 6 a 7 7
}

do_catchsql_test 6.3 {
  SELECT x, lag(x) FILTER (WHERE (x%2)=0) OVER w FROM t1 
  WINDOW w AS (ORDER BY x)
} {1 {FILTER clause may only be used with aggregate window functions}}
 
#-------------------------------------------------------------------------
# Attempt to use a window function as an aggregate. And other errors.
#
reset_db
do_execsql_test 7.0 {
  CREATE TABLE t1(x, y);
  INSERT INTO t1 VALUES(1, 2);
  INSERT INTO t1 VALUES(3, 4);
  INSERT INTO t1 VALUES(5, 6);
  INSERT INTO t1 VALUES(7, 8);
  INSERT INTO t1 VALUES(9, 10);
}

do_catchsql_test 7.1.1 {
  SELECT nth_value(x, 1) FROM t1;
} {1 {misuse of window function nth_value()}}
do_catchsql_test 7.1.2 {
  SELECT * FROM t1 WHERE nth_value(x, 1) OVER (ORDER BY y);
} {1 {misuse of window function nth_value()}}
do_catchsql_test 7.1.3 {
  SELECT count(*) FROM t1 GROUP BY y HAVING nth_value(x, 1) OVER (ORDER BY y);
} {1 {misuse of window function nth_value()}}
do_catchsql_test 7.1.4 {
  SELECT count(*) FROM t1 GROUP BY nth_value(x, 1) OVER (ORDER BY y);
} {1 {misuse of window function nth_value()}}
do_catchsql_test 7.1.5 {
  SELECT count(*) FROM t1 LIMIT nth_value(x, 1) OVER (ORDER BY y);
} {1 {no such column: x}}
do_catchsql_test 7.1.6 {
  SELECT trim(x) OVER (ORDER BY y) FROM t1;
} {1 {trim() may not be used as a window function}}


finish_test

  ORDER BY a;
}

execsql_test 3.4 {
  SELECT a, max(a) FILTER (WHERE (a%2)=0) OVER w FROM t5 
  WINDOW w AS (ORDER BY a)
}

execsql_test 3.5.1 {
  SELECT a, max(c) OVER (ORDER BY a ROWS BETWEEN 1 PRECEDING AND 2 PRECEDING)
  FROM t5
}
execsql_test 3.5.2 {
  SELECT a, max(c) OVER (ORDER BY a ROWS BETWEEN 1 PRECEDING AND 1 PRECEDING)
  FROM t5
}
execsql_test 3.5.3 {
  SELECT a, max(c) OVER (ORDER BY a ROWS BETWEEN 0 PRECEDING AND 0 PRECEDING)
  FROM t5
}

execsql_test 3.6.1 {
  SELECT a, max(c) OVER (ORDER BY a ROWS BETWEEN 2 FOLLOWING AND 1 FOLLOWING)
  FROM t5
}
execsql_test 3.6.2 {
  SELECT a, max(c) OVER (ORDER BY a ROWS BETWEEN 1 FOLLOWING AND 1 FOLLOWING)
  FROM t5
}
execsql_test 3.6.3 {
  SELECT a, max(c) OVER (ORDER BY a ROWS BETWEEN 0 FOLLOWING AND 0 FOLLOWING)
  FROM t5
}


finish_test

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}






do_execsql_test 3.4 {
  SELECT a, max(a) FILTER (WHERE (a%2)=0) OVER w FROM t5 
  WINDOW w AS (ORDER BY a)
} {1 {}   2 2   3 2   4 4   5 4}

do_execsql_test 3.5.1 {
  SELECT a, max(c) OVER (ORDER BY a ROWS BETWEEN 1 PRECEDING AND 2 PRECEDING)
  FROM t5
} {1 {}   2 {}   3 {}   4 {}   5 {}}

do_execsql_test 3.5.2 {
  SELECT a, max(c) OVER (ORDER BY a ROWS BETWEEN 1 PRECEDING AND 1 PRECEDING)
  FROM t5
} {1 {}   2 one   3 two   4 three   5 four}

do_execsql_test 3.5.3 {
  SELECT a, max(c) OVER (ORDER BY a ROWS BETWEEN 0 PRECEDING AND 0 PRECEDING)
  FROM t5
} {1 one   2 two   3 three   4 four   5 five}

do_execsql_test 3.6.1 {
  SELECT a, max(c) OVER (ORDER BY a ROWS BETWEEN 2 FOLLOWING AND 1 FOLLOWING)
  FROM t5
} {1 {}   2 {}   3 {}   4 {}   5 {}}

do_execsql_test 3.6.2 {
  SELECT a, max(c) OVER (ORDER BY a ROWS BETWEEN 1 FOLLOWING AND 1 FOLLOWING)
  FROM t5
} {1 two   2 three   3 four   4 five   5 {}}

do_execsql_test 3.6.3 {
  SELECT a, max(c) OVER (ORDER BY a ROWS BETWEEN 0 FOLLOWING AND 0 FOLLOWING)
  FROM t5
} {1 one   2 two   3 three   4 four   5 five}

finish_test