public string GetSelectScalarSql<T>(
	Expression<Func<IEnumerable<E>, T>> expression,
	Expression<Func<E, bool>> where = null,
	Object param = null
)

Parameters

expression

Type: System.Linq.ExpressionsExpressionFuncIEnumerableE, T
Scalar expression

where (Optional)

Type: System.Linq.ExpressionsExpressionFuncE, Boolean
Where expression. You can use members of E or param. Other values will be evaluated.

param (Optional)

Type: SystemObject
Query parameters

Type Parameters

T

Result type

Return Value

You need to pass expression for retrive scalar data form database:

var sql = GetSelectScalarSql{T}(l => l.Average(e => e.Price));
// select avg(Price) from Table;

T is the return type for expression. Where expression used like in GetSelectSql.

Reference