SQLite

  }else{
    /* Neither operand is NULL.  Do a comparison. */
    affinity = pOp->p5 & SQLITE_AFF_MASK;
    if( affinity>=SQLITE_AFF_NUMERIC ){
      if( (flags1 | flags3)&MEM_Str ){
        if( (flags1 & (MEM_Int|MEM_Real|MEM_Str))==MEM_Str ){
          applyNumericAffinity(pIn1,0);
          testcase( flags3!=pIn3->flags ); /* Possible if pIn1==pIn3 */
          flags3 = pIn3->flags;
        }
        if( (flags3 & (MEM_Int|MEM_Real|MEM_Str))==MEM_Str ){
          applyNumericAffinity(pIn3,0);
        }
      }
      /* Handle the common case of integer comparison here, as an
      ** optimization, to avoid a call to sqlite3MemCompare() */
      if( (pIn1->flags & pIn3->flags & MEM_Int)!=0 ){
        if( pIn3->u.i > pIn1->u.i ){ res = +1; goto compare_op; }
        if( pIn3->u.i < pIn1->u.i ){ res = -1; goto compare_op; }
        res = 0;
        goto compare_op;
      }
    }else if( affinity==SQLITE_AFF_TEXT ){
      if( (flags1 & MEM_Str)==0 && (flags1 & (MEM_Int|MEM_Real))!=0 ){
        testcase( pIn1->flags & MEM_Int );
        testcase( pIn1->flags & MEM_Real );
        sqlite3VdbeMemStringify(pIn1, encoding, 1);
        testcase( (flags1&MEM_Dyn) != (pIn1->flags&MEM_Dyn) );
        flags1 = (pIn1->flags & ~MEM_TypeMask) | (flags1 & MEM_TypeMask);
        testcase( flags3!=pIn3->flags ); /* Possible if pIn1==pIn3 */
        flags3 = pIn3->flags;
      }
      if( (flags3 & MEM_Str)==0 && (flags3 & (MEM_Int|MEM_Real))!=0 ){
        testcase( pIn3->flags & MEM_Int );
        testcase( pIn3->flags & MEM_Real );
        sqlite3VdbeMemStringify(pIn3, encoding, 1);
        testcase( (flags3&MEM_Dyn) != (pIn3->flags&MEM_Dyn) );
        flags3 = (pIn3->flags & ~MEM_TypeMask) | (flags3 & MEM_TypeMask);
      }
    }
    assert( pOp->p4type==P4_COLLSEQ || pOp->p4.pColl==0 );








    res = sqlite3MemCompare(pIn3, pIn1, pOp->p4.pColl);
  }
compare_op:
  switch( pOp->opcode ){
    case OP_Eq:    res2 = res==0;     break;
    case OP_Ne:    res2 = res;        break;
    case OP_Lt:    res2 = res<0;      break;
    case OP_Le:    res2 = res<=0;     break;
    case OP_Gt:    res2 = res>0;      break;
    default:       res2 = res>=0;     break;

    rc = pColl->xCmp(pColl->pUser, n1, v1, n2, v2);
    if( (v1==0 || v2==0) && prcErr ) *prcErr = SQLITE_NOMEM_BKPT;
    sqlite3VdbeMemRelease(&c1);
    sqlite3VdbeMemRelease(&c2);
    return rc;
  }
}

/*
** The input pBlob is guaranteed to be a Blob that is not marked
** with MEM_Zero.  Return true if it could be a zero-blob.
*/
static int isZeroBlob(const Mem *pBlob){
  int i;
  for(i=0; i<pBlob->n && pBlob->z[i]==0; i++){}
  return i==pBlob->n;
}

/*
** Compare two blobs.  Return negative, zero, or positive if the first
** is less than, equal to, or greater than the second, respectively.
** If one blob is a prefix of the other, then the shorter is the lessor.
*/
static SQLITE_NOINLINE int sqlite3BlobCompare(const Mem *pB1, const Mem *pB2){
  int c;
  int n1 = pB1->n;
  int n2 = pB2->n;

  /* It is possible to have a Blob value that has some non-zero content
  ** followed by zero content.  But that only comes up for Blobs formed
  ** by the OP_MakeRecord opcode, and such Blobs never get passed into
  ** sqlite3MemCompare(). */
  assert( (pB1->flags & MEM_Zero)==0 || n1==0 );
  assert( (pB2->flags & MEM_Zero)==0 || n2==0 );

  if( (pB1->flags|pB2->flags) & MEM_Zero ){
    if( pB1->flags & pB2->flags & MEM_Zero ){
      return pB1->u.nZero - pB2->u.nZero;
    }else if( pB1->flags & MEM_Zero ){
      if( !isZeroBlob(pB2) ) return -1;
      return pB1->u.nZero - n2;
    }else{
      if( !isZeroBlob(pB1) ) return +1;
      return n1 - pB2->u.nZero;
    }
  }
  c = memcmp(pB1->z, pB2->z, n1>n2 ? n2 : n1);
  if( c ) return c;
  return n1 - n2;
}

/*
** Do a comparison between a 64-bit signed integer and a 64-bit floating-point
** number.  Return negative, zero, or positive if the first (i64) is less than,
** equal to, or greater than the second (double).
*/