SQLite

** SELECT * FROM t1 WHERE a;
** SELECT a AS b FROM t1 WHERE b;
** SELECT * FROM t1 WHERE (select a from t1);
*/
char sqlite3ExprAffinity(Expr *pExpr){
  int op;
  if( pExpr->flags & EP_Generic ) return 0;
  while( ExprHasProperty(pExpr, EP_Skip) ){
    assert( pExpr->op==TK_COLLATE );
    pExpr = pExpr->pLeft;
    assert( pExpr!=0 );
  }
  op = pExpr->op;
  if( op==TK_SELECT ){
    assert( pExpr->flags&EP_xIsSelect );
    return sqlite3ExprAffinity(pExpr->x.pSelect->pEList->a[0].pExpr);
  }
  if( op==TK_REGISTER ) op = pExpr->op2;
#ifndef SQLITE_OMIT_CAST

}

/*
** Skip over any TK_COLLATE operators and any unlikely()
** or likelihood() function at the root of an expression.
*/
Expr *sqlite3ExprSkipCollate(Expr *pExpr){
  while( pExpr && ExprHasProperty(pExpr, EP_Skip|EP_Unlikely) ){
    if( ExprHasProperty(pExpr, EP_Unlikely) ){
      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
      assert( pExpr->x.pList->nExpr>0 );
      assert( pExpr->op==TK_FUNCTION );
      pExpr = pExpr->x.pList->a[0].pExpr;
    }else{
      assert( pExpr->op==TK_COLLATE );

          no_such_func = 1;
        }else{
          wrong_num_args = 1;
        }
      }else{
        is_agg = pDef->xFinalize!=0;
        if( pDef->funcFlags & SQLITE_FUNC_UNLIKELY ){
          ExprSetProperty(pExpr, EP_Unlikely);
          if( n==2 ){
            pExpr->iTable = exprProbability(pList->a[1].pExpr);
            if( pExpr->iTable<0 ){
              sqlite3ErrorMsg(pParse,
                "second argument to likelihood() must be a "
                "constant between 0.0 and 1.0");
              pNC->nErr++;

#define EP_VarSelect 0x000020 /* pSelect is correlated, not constant */
#define EP_DblQuoted 0x000040 /* token.z was originally in "..." */
#define EP_InfixFunc 0x000080 /* True for an infix function: LIKE, GLOB, etc */
#define EP_Collate   0x000100 /* Tree contains a TK_COLLATE operator */
#define EP_Generic   0x000200 /* Ignore COLLATE or affinity on this tree */
#define EP_IntValue  0x000400 /* Integer value contained in u.iValue */
#define EP_xIsSelect 0x000800 /* x.pSelect is valid (otherwise x.pList is) */
#define EP_Skip      0x001000 /* Operator does not contribute to affinity */
#define EP_Reduced   0x002000 /* Expr struct EXPR_REDUCEDSIZE bytes only */
#define EP_TokenOnly 0x004000 /* Expr struct EXPR_TOKENONLYSIZE bytes only */
#define EP_Win       0x008000 /* Contains window functions */
#define EP_MemToken  0x010000 /* Need to sqlite3DbFree() Expr.zToken */
#define EP_NoReduce  0x020000 /* Cannot EXPRDUP_REDUCE this Expr */
#define EP_Unlikely  0x040000 /* unlikely() or likelihood() function */
#define EP_ConstFunc 0x080000 /* A SQLITE_FUNC_CONSTANT or _SLOCHNG function */

# EVIDENCE-OF: R-22887-63324 The unlikely(X) function is a no-op that
# the code generator optimizes away so that it consumes no CPU cycles at
# run-time (that is, during calls to sqlite3_step()).
#
do_test func3-5.39 {
  db eval {EXPLAIN SELECT unlikely(min(1.0+'2.0',4*11))}
} [db eval {EXPLAIN SELECT min(1.0+'2.0',4*11)}]

# Unlikely() does not preserve the affinity of X.
# ticket https://www.sqlite.org/src/tktview/0c620df60b
#
do_execsql_test func3-5.40 {
  SELECT likely(CAST(1 AS INT))=='1';
} 0
do_execsql_test func3-5.41 {
  SELECT unlikely(CAST(1 AS INT))=='1';
} 0
do_execsql_test func3-5.41 {
  SELECT likelihood(CAST(1 AS INT),0.5)=='1';
} 0


# EVIDENCE-OF: R-23735-03107 The likely(X) function returns the argument
# X unchanged.
#
do_execsql_test func3-5.50 {
  SELECT likely(9223372036854775807);