/// <summary>
/// Creates instance of query aggregate function.
/// </summary>
/// <param name="function">Sql function name</param>
/// <param name="key">Sql function keyword (ALL, DISTINCT)</param>
/// <param name="expression"></param>
public QueryAggregate(QueryAggregateFunction function, QueryKey key, object expression)
{
// Initialization.
QueryFunction = function;
Expression = expression;
QueryKey = key;
}
/// <summary>
/// Creates instance of query aggregate function.
/// </summary>
/// <param name="function">Sql function</param>
/// <param name="parameters">Function parameters and expressions</param>
public QueryFunction(QueryAggregateFunction function, params object[] parameters)
{
// Initialize.
PartOfGroupBy = false;
FunctionName = function.ToString().ToUpper();
SeperateParameters(parameters);
}
public string GenerateAggregateQuery(DatabaseQuery query, QueryAggregateFunction function, string propertyName)
{
var sqlFunction = function.ToString();
var columnValueExpression = MapColumn(propertyName);
if (function == QueryAggregateFunction.Average)
{
sqlFunction = "AVG";
var propertyType = query.EntityType.GetProperty(propertyName).PropertyType;
if (propertyType == typeof(int) || propertyType == typeof(int?))
{
columnValueExpression = $"CAST({columnValueExpression} AS decimal)";
}
}
return($"SELECT {sqlFunction}({columnValueExpression}) FROM {GetTables()}" +
GenerateWhere(query));
}
public object Aggregate(QueryAggregateFunction function, string propertyName)
{
return(Provider.Aggregate(this, function, propertyName));
}
/// <summary>
/// Creates instance of query aggregate function.
/// </summary>
/// <param name="function"></param>
/// <param name="key"></param>
/// <param name="expression"></param>
/// <param name="partitionExpression"></param>
/// <param name="overExpression"></param>
public QueryAggregate(QueryAggregateFunction function, string expression, string partitionExpression, string overExpression)
{
}
/// <summary>
/// Creates instance of query aggregate function.
/// </summary>
/// <param name="function"></param>
/// <param name="key"></param>
/// <param name="expression"></param>
public QueryAggregate(QueryAggregateFunction function, string[] expression, string[] overExpression)
{
}
public object Aggregate(DatabaseQuery query, QueryAggregateFunction function, string propertyName)
{
var command = GenerateAggregateQuery(query, function, propertyName);
return(ExecuteScalar(command, CommandType.Text, GenerateParameters(query.Parameters)));
}
