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Overview
Comment:Add comments to window.c describing how other window frames will be implemented.
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SHA3-256: 16168146b202915252f9375aef38e65ca20c5d4aa906e851d4d3a484db57562d
User & Date: dan 2018-05-22 20:35:37
Context
2018-05-22
20:36
Merge latest trunk changes into this branch. (check-in: cdb68d2c user: dan tags: exp-window-functions)
20:35
Add comments to window.c describing how other window frames will be implemented. (check-in: 16168146 user: dan tags: exp-window-functions)
2018-05-21
19:45
Begin adding support for more esoteric window frames. (check-in: bc4b81d6 user: dan tags: exp-window-functions)
Changes
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Changes to src/window.c. 

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**
** ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
** ROWS BETWEEN CURRENT ROW AND CURRENT ROW
** ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
**
**========================================================================
**
** ROWS BETWEEN UNBOUNDED PRECEDING AND <expr> PRECEDING
** ROWS BETWEEN <expr> PRECEDING    AND <expr> PRECEDING

































** ROWS BETWEEN <expr> PRECEDING    AND CURRENT ROW


** ROWS BETWEEN UNBOUNDED PRECEDING AND <expr> FOLLOWING




** ROWS BETWEEN <expr> PRECEDING    AND <expr> FOLLOWING
** ROWS BETWEEN CURRENT ROW         AND <expr> FOLLOWING















** ROWS BETWEEN <expr> FOLLOWING    AND <expr> FOLLOWING
** ROWS BETWEEN <expr> PRECEDING    AND UNBOUNDED FOLLOWING
















** ROWS BETWEEN <expr> FOLLOWING    AND UNBOUNDED FOLLOWING
**
**   Cases that involve <expr> PRECEDING or <expr> FOLLOWING.


**
**   ...
**     Insert (record in eph-table)
**   sqlite3WhereEnd()
**
*/
void sqlite3WindowCodeStep(
  Parse *pParse, 
  Select *p,
  WhereInfo *pWInfo,
  int regGosub, 
................................................................................
    int nPeer = (pOrderBy ? pOrderBy->nExpr : 0);
    int addrGoto = 0;
    int addrJump = 0;

    if( pPart ){
      int regNewPart = reg + pMWin->nBufferCol;
      KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pPart, 0, 0);
      addr = sqlite3VdbeAddOp3(v, OP_Compare, regNewPart, pMWin->regPart, nPart);
      sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO);
      addrJump = sqlite3VdbeAddOp3(v, OP_Jump, addr+2, 0, addr+2);
      for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
        sqlite3VdbeAddOp2(v, OP_AggFinal, pWin->regAccum, pWin->nArg);
        sqlite3VdbeAppendP4(v, pWin->pFunc, P4_FUNCDEF);
        sqlite3VdbeAddOp2(v, OP_Copy, pWin->regAccum, pWin->regResult);
      }
................................................................................
      if( addrGoto ) sqlite3VdbeJumpHere(v, addrGoto);
    }

    sqlite3VdbeAddOp2(v, OP_Gosub, regGosub, addrGosub);
    sqlite3VdbeAddOp1(v, OP_ResetSorter, pMWin->iEphCsr);
    sqlite3VdbeAddOp3(
        v, OP_Copy, reg+pMWin->nBufferCol, pMWin->regPart, nPart+nPeer-1
        );

    sqlite3VdbeJumpHere(v, addrJump);
  }

  /* Invoke step function for window functions */
  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
    sqlite3VdbeAddOp3(v, OP_AggStep0, 0, reg+pWin->iArgCol, pWin->regAccum);








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**
** ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
** ROWS BETWEEN CURRENT ROW AND CURRENT ROW
** ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
**
**========================================================================
**

** ROWS BETWEEN <expr> PRECEDING    AND <expr> FOLLOWING
**
**   ...
**     if( new partition ){
**       Gosub flush_partition
**     }
**     Insert (record in eph-table)
**   sqlite3WhereEnd()
**   Gosub flush_partition
**
** flush_partition:
**   OpenDup (csr -> csr2)
**   OpenDup (csr -> csr3)
**   regPrec = <expr1>            // PRECEDING expression
**   regFollow = <expr2>          // FOLLOWING expression
**   if( regPrec<0 || regFollow<0 ) throw exception!
**   Rewind (csr,csr2,csr3)       // if EOF goto flush_partition_done
**     Aggstep (csr3)
**     Next(csr3)                 // if EOF fall-through
**     if( (regFollow--)<=0 ){
**       AggFinal (xValue)
**       Gosub addrGosub
**       Next(csr)                // if EOF goto flush_partition_done
**       if( (regPrec--)<=0 ){
**         AggStep (csr2, xInverse)
**         Next(csr2)
**       }
**     }
** flush_partition_done:
**   Close (csr2)
**   Close (csr3)
**   ResetSorter (csr)
**   Return
**
** ROWS BETWEEN <expr> PRECEDING    AND CURRENT ROW
** ROWS BETWEEN CURRENT ROW         AND <expr> FOLLOWING
** ROWS BETWEEN <expr> PRECEDING    AND UNBOUNDED FOLLOWING
** ROWS BETWEEN UNBOUNDED PRECEDING AND <expr> FOLLOWING
**
**   These are similar to the above. For "CURRENT ROW", intialize the
**   register to 0. For "UNBOUNDED ..." to infinity.
**
** ROWS BETWEEN <expr> PRECEDING    AND <expr> PRECEDING

**
**   Replace the bit after "Rewind" in the above with:
**
**     if( (regFollow--)<=0 ){
**       AggStep (csr3)
**       Next (csr3)
**     }
**     AggFinal (xValue)
**     Gosub addrGosub
**     Next(csr)                  // if EOF goto flush_partition_done
**     if( (regPrec--)<=0 ){
**       AggStep (csr2, xInverse)
**       Next (csr2)
**     }
**
** ROWS BETWEEN <expr> FOLLOWING    AND <expr> FOLLOWING

**
**   regFollow = regFollow - regPrec
**   Rewind (csr,csr2,csr3)       // if EOF goto flush_partition_done
**     Aggstep (csr3)
**     Next(csr3)                 // if EOF fall-through
**     if( (regFollow--)<=0 ){
**       AggStep (csr2, xInverse)
**       Next (csr2)
**       if( (regPrec--)<=0 ){
**         AggFinal (xValue)
**         Gosub addrGosub
**         Next(csr)              // if EOF goto flush_partition_done
**       }
**     }
**
** ROWS BETWEEN UNBOUNDED PRECEDING AND <expr> PRECEDING
** ROWS BETWEEN <expr> FOLLOWING    AND UNBOUNDED FOLLOWING
**

**   Similar to the above, except with regPrec or regFollow set to infinity,
**   as appropriate.
**
**


**
*/
void sqlite3WindowCodeStep(
  Parse *pParse, 
  Select *p,
  WhereInfo *pWInfo,
  int regGosub, 
................................................................................
    int nPeer = (pOrderBy ? pOrderBy->nExpr : 0);
    int addrGoto = 0;
    int addrJump = 0;

    if( pPart ){
      int regNewPart = reg + pMWin->nBufferCol;
      KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pPart, 0, 0);
      addr = sqlite3VdbeAddOp3(v, OP_Compare, regNewPart, pMWin->regPart,nPart);
      sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO);
      addrJump = sqlite3VdbeAddOp3(v, OP_Jump, addr+2, 0, addr+2);
      for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
        sqlite3VdbeAddOp2(v, OP_AggFinal, pWin->regAccum, pWin->nArg);
        sqlite3VdbeAppendP4(v, pWin->pFunc, P4_FUNCDEF);
        sqlite3VdbeAddOp2(v, OP_Copy, pWin->regAccum, pWin->regResult);
      }
................................................................................
      if( addrGoto ) sqlite3VdbeJumpHere(v, addrGoto);
    }

    sqlite3VdbeAddOp2(v, OP_Gosub, regGosub, addrGosub);
    sqlite3VdbeAddOp1(v, OP_ResetSorter, pMWin->iEphCsr);
    sqlite3VdbeAddOp3(
        v, OP_Copy, reg+pMWin->nBufferCol, pMWin->regPart, nPart+nPeer-1
    );

    sqlite3VdbeJumpHere(v, addrJump);
  }

  /* Invoke step function for window functions */
  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
    sqlite3VdbeAddOp3(v, OP_AggStep0, 0, reg+pWin->iArgCol, pWin->regAccum);

Changes to test/window2.tcl. 

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execsql_test 2.3 {
  SELECT a, sum(d) OVER (
    ORDER BY d
    ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
  ) FROM t1
}















finish_test










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execsql_test 2.3 {
  SELECT a, sum(d) OVER (
    ORDER BY d
    ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
  ) FROM t1
}

execsql_test 2.4 {
  SELECT a, sum(d) OVER (
    ORDER BY d
    ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING
  ) FROM t1
}

execsql_test 2.5 {
  SELECT a, sum(d) OVER (
    ORDER BY d
    ROWS BETWEEN 1 PRECEDING AND 1 PRECEDING
  ) FROM t1
}

finish_test

Changes to test/window2.test. 

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do_execsql_test 2.3 {
  SELECT a, sum(d) OVER (
    ORDER BY d
    ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
  ) FROM t1
} {1 21   2 21   3 21   4 21   5 21   6 21}















finish_test








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do_execsql_test 2.3 {
  SELECT a, sum(d) OVER (
    ORDER BY d
    ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
  ) FROM t1
} {1 21   2 21   3 21   4 21   5 21   6 21}

do_execsql_test 2.4 {
  SELECT a, sum(d) OVER (
    ORDER BY d
    ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING
  ) FROM t1
} {1 3   2 6   3 9   4 12   5 15   6 11}

do_execsql_test 2.5 {
  SELECT a, sum(d) OVER (
    ORDER BY d
    ROWS BETWEEN 1 PRECEDING AND 1 PRECEDING
  ) FROM t1
} {1 {}   2 1   3 2   4 3   5 4   6 5}

finish_test

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