SQLite

** give a NULL output.
*/
case OP_And:              /* same as TK_AND, in1, in2, out3 */
case OP_Or: {             /* same as TK_OR, in1, in2, out3 */
  int v1;    /* Left operand:  0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */
  int v2;    /* Right operand: 0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */

  v1 = sqlite3VdbeBooleanValue(&aMem[pOp->p1], 2);





  v2 = sqlite3VdbeBooleanValue(&aMem[pOp->p2], 2);





  if( pOp->opcode==OP_And ){
    static const unsigned char and_logic[] = { 0, 0, 0, 0, 1, 2, 0, 2, 2 };
    v1 = and_logic[v1*3+v2];
  }else{
    static const unsigned char or_logic[] = { 0, 1, 2, 1, 1, 1, 2, 1, 2 };
    v1 = or_logic[v1*3+v2];
  }

** boolean complement in register P2.  If the value in register P1 is 
** NULL, then a NULL is stored in P2.
*/
case OP_Not: {                /* same as TK_NOT, in1, out2 */
  pIn1 = &aMem[pOp->p1];
  pOut = &aMem[pOp->p2];
  if( (pIn1->flags & MEM_Null)==0 ){
    sqlite3VdbeMemSetInt64(pOut, !sqlite3VdbeBooleanValue(pIn1,0));
  }else{
    sqlite3VdbeMemSetNull(pOut);
  }
  break;
}

/* Opcode: BitNot P1 P2 * * *

/* Opcode: If P1 P2 P3 * *
**
** Jump to P2 if the value in register P1 is true.  The value
** is considered true if it is numeric and non-zero.  If the value
** in P1 is NULL then take the jump if and only if P3 is non-zero.
*/
case OP_If:  {               /* jump, in1 */
  int c;
  c = sqlite3VdbeBooleanValue(&aMem[pOp->p1], pOp->p3);
  VdbeBranchTaken(c!=0, 2);
  if( c ) goto jump_to_p2;
  break;
}

/* Opcode: IfNot P1 P2 P3 * *
**
** Jump to P2 if the value in register P1 is False.  The value
** is considered false if it has a numeric value of zero.  If the value
** in P1 is NULL then take the jump if and only if P3 is non-zero.
*/

case OP_IfNot: {            /* jump, in1 */
  int c;
  c = !sqlite3VdbeBooleanValue(&aMem[pOp->p1], !pOp->p3);










  VdbeBranchTaken(c!=0, 2);

  if( c ) goto jump_to_p2;

  break;
}

/* Opcode: IsNull P1 P2 * * *
** Synopsis: if r[P1]==NULL goto P2
**
** Jump to P2 if the value in register P1 is NULL.

void sqlite3VdbeMemSetZeroBlob(Mem*,int);
void sqlite3VdbeMemSetRowSet(Mem*);
int sqlite3VdbeMemMakeWriteable(Mem*);
int sqlite3VdbeMemStringify(Mem*, u8, u8);
i64 sqlite3VdbeIntValue(Mem*);
int sqlite3VdbeMemIntegerify(Mem*);
double sqlite3VdbeRealValue(Mem*);
int sqlite3VdbeBooleanValue(Mem*, int ifNull);
void sqlite3VdbeIntegerAffinity(Mem*);
int sqlite3VdbeMemRealify(Mem*);
int sqlite3VdbeMemNumerify(Mem*);
void sqlite3VdbeMemCast(Mem*,u8,u8);
int sqlite3VdbeMemFromBtree(BtCursor*,u32,u32,Mem*);
void sqlite3VdbeMemRelease(Mem *p);
int sqlite3VdbeMemFinalize(Mem*, FuncDef*);

  }else if( pMem->flags & (MEM_Str|MEM_Blob) ){
    return memRealValue(pMem);
  }else{
    /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
    return (double)0;
  }
}

/*
** Return 1 if pMem represents true, and return 0 if pMem represents false.
** Return the value ifNull if pMem is NULL.  
*/
int sqlite3VdbeBooleanValue(Mem *pMem, int ifNull){
  if( pMem->flags & MEM_Int ) return pMem->u.i!=0;
  if( pMem->flags & MEM_Null ) return ifNull;
  return sqlite3VdbeRealValue(pMem)!=0.0;
}

/*
** The MEM structure is already a MEM_Real.  Try to also make it a
** MEM_Int if we can.
*/
void sqlite3VdbeIntegerAffinity(Mem *pMem){
  i64 ix;

do_execsql_test expr-13.8 {
  SELECT "" <= '';
} {1}
do_execsql_test expr-13.9 {
  SELECT '' <= "";
} {1}

# 2018-02-26. Ticket https://www.sqlite.org/src/tktview/36fae083b450e3af85
# 
do_execsql_test expr-14.1 {
  DROP TABLE IF EXISTS t1;
  CREATE TABLE t1(x);
  INSERT INTO t1 VALUES(0),(1),(NULL),(0.5),('1x'),('0x');
  SELECT count(*) FROM t1
   WHERE (x OR (8==9)) != (CASE WHEN x THEN 1 ELSE 0 END);
} {0}
do_execsql_test expr-14.2 {
  SELECT count(*) FROM t1
   WHERE (x OR (8==9)) != (NOT NOT x);
} {0}
do_execsql_test expr-14.3 {
  SELECT sum(NOT x) FROM t1
   WHERE x
} {0}
do_execsql_test expr-14.4 {
  SELECT sum(CASE WHEN x THEN 0 ELSE 1 END) FROM t1
   WHERE x
} {0}



finish_test