public static DbValue NULLIF(DbFunctionTools tools, DbFunctionArguments args)
{
string FunctionName = "NULLIF";
args.EnsureCount(FunctionName, 2);
DbType arg0type;
ByteSlice arg0 = args[0].Eval(out arg0type);
ImmediateValue argval = null;
argval = tools.AllocValue(arg0type.ID);
argval.SetValue(arg0);
DbFunctionArguments compareargs = new DbFunctionArguments(new DbValue[2]);
compareargs[0] = argval;
compareargs[1] = args[1];
DbValue result = COMPARE(tools, compareargs);
int iresult = tools.GetInt(result);
if (iresult == 0)
{
List <byte> buf = tools.AllocBuffer(arg0type.Size);
buf.Add(1);
for (int i = 0; i < arg0type.Size - 1; i++)
{
buf.Add(0);
}
return(tools.AllocValue(ByteSlice.Prepare(buf), arg0type));
}
else
{
return(args[0]);
}
}
public static DbValue MAX(DbFunctionTools tools, DbAggregatorArguments args)
{
string AggregatorName = "MAX";
DbValue highest = null;
DbValue nullest = null;
DbFunctionArguments compareargs = new DbFunctionArguments(new DbValue[2]);
ImmediateValue argval = null;
for (int iarg = 0; iarg < args.Length; iarg++)
{
args[iarg].EnsureCount(AggregatorName, 1);
DbType arg0type;
ByteSlice arg0 = args[iarg][0].Eval(out arg0type);
if (Types.IsNullValue(arg0))
{
if (null == nullest)
{
nullest = tools.AllocValue(arg0, arg0type);
}
}
else
{
if (null == argval)
{
argval = tools.AllocValue(arg0type.ID);
}
argval.SetValue(arg0);
compareargs[0] = argval;
compareargs[1] = highest;
if (null == highest || tools.GetInt(DbFunctions.COMPARE(tools, compareargs)) > 0)
{
highest = argval; // Keep this one.
argval = null; // New one next time.
}
}
}
if (null == highest)
{
if (null == nullest)
{
return(tools.AllocNullValue());
}
return(nullest);
}
return(highest);
}
public ImmediateValue AllocValue(DbTypeID typeID)
{
if (curval >= values.Count)
{
ImmediateValue val = new ImmediateValue(null, ByteSlice.Prepare(), DbType.Prepare(0, typeID));
values.Add(val);
curval++;
return(val);
}
else
{
ImmediateValue val = values[curval++];
val._value = ByteSlice.Prepare();
val._type = DbType.Prepare(0, typeID);
return(val);
}
}
public DbValue AllocValue(ByteSlice value, DbType type)
{
if (curval >= values.Count)
{
ImmediateValue val = new ImmediateValue(null, value, type);
values.Add(val);
curval++;
return(val);
}
else
{
ImmediateValue val = values[curval++];
val._value = value;
val._type = type;
return(val);
}
}
public ImmediateValue AllocValue(DbTypeID typeID)
{
if (curval >= values.Count)
{
ImmediateValue val = new ImmediateValue(null, ByteSlice.Prepare(), DbType.Prepare(0, typeID));
values.Add(val);
curval++;
return val;
}
else
{
ImmediateValue val = values[curval++];
val._value = ByteSlice.Prepare();
val._type = DbType.Prepare(0, typeID);
return val;
}
}
public DbValue AllocValue(ByteSlice value, DbType type)
{
if (curval >= values.Count)
{
ImmediateValue val = new ImmediateValue(null, value, type);
values.Add(val);
curval++;
return val;
}
else
{
ImmediateValue val = values[curval++];
val._value = value;
val._type = type;
return val;
}
}