синтаксис для sql запроса с условиями EXIST, NOT EXIST

	Select select = new Select(UserConnection)
		.Column("DestinationRecordId")
		.Column("Id")
		.From("LookupConflict")
		.Where("LookupSchemaName").IsEqual(Column.Parameter(node.Values["Lookup"]))
		.And("LookupSchemaDisplayColumnName").IsEqual(Column.Parameter(node.Values["Column"]))
		.And("LookupSchemaDisplayColumnValue").IsEqual(Column.Parameter(node.Values["FileName"]))
		.And().Exists(
			new Select(UserConnection)
				.Column("Id")
				.From("Contact")
				.Where("Contact", "Id").IsEqual("DestinationRecordId"))
		.And().Not().Exists(
			new Select(UserConnection)
				.Column("ContactId")
				.From("Employee")
				.Where("Employee", "ContactId").IsEqual("DestinationRecordId")) as Select;