private string Base(Expression exp)
{
var cached = (CachedExpression)exp;
if (cached.Sql != null)
{
return(cached.Sql);
}
cached.Sql = exp switch
{
UnionExpression e => Union(e),
SelectExpression e => Select(e),
WhereExpression e => Where(e),
MaxExpression e => Max(e),
MinExpression e => Min(e),
SumExpression e => Sum(e),
CountExpression e => Count(e),
TakeExpression e => Take(e),
SkipExpression e => Skip(e),
FirstExpression e => First(e),
DistinctExpression e => Distinct(e),
OrderByExpression e => OrderBy(e),
OrderByDescendingExpression e => OrderByDescending(e),
_ => throw new InvalidEnumArgumentException()
};
return(cached.Sql);
}
private static Expression HandleMax(HandlerContext handlerContext)
{
var maxExpression
= new MaxExpression(handlerContext.SelectExpression.Projection.Single());
handlerContext.SelectExpression.SetProjectionExpression(maxExpression);
return((Expression)_transformClientExpressionMethodInfo
.MakeGenericMethod(maxExpression.Type)
.Invoke(null, new object[] { handlerContext }));
}
public Completion Max(object a, object b)
{
ExecutionEnvironment e = new ExecutionEnvironment();
e.RegisterValue("a", a);
e.RegisterValue("b", b);
MaxExpression abs = new MaxExpression();
abs.Args[0] = new Identifier("a");
abs.Args[1] = new Identifier("b");
return(abs.Execute(e));
}
public virtual Expression VisitMaxExpression(MaxExpression maxExpression)
{
Check.NotNull(maxExpression, "maxExpression");
_sql.Append("MAX(");
VisitExpression(maxExpression.ColumnExpression);
_sql.Append(")");
return(maxExpression);
}
public virtual Expression VisitMax(MaxExpression maxExpression)
{
Check.NotNull(maxExpression, nameof(maxExpression));
_sql.Append("MAX(");
Visit(maxExpression.Expression);
_sql.Append(")");
return(maxExpression);
}
public virtual Expression VisitMax(MaxExpression maxExpression)
{
Check.NotNull(maxExpression, nameof(maxExpression));
_relationalCommandBuilder.Append("MAX(");
Visit(maxExpression.Expression);
_relationalCommandBuilder.Append(")");
return(maxExpression);
}
private string Max(MaxExpression exp) => $"SELECT MAX({Secondary.Serialize(exp.Selector.Body)}) FROM ({Serialize(exp.Sub)}) AS this";