/// <summary>
/// 查询
/// </summary>
/// <param name="expression"></param>
/// <param name="orderBy">排序字段</param>
/// <returns></returns>
public SqlExpressionCore <T> Select(Expression <Func <T, object> > expression = null, string orderBy = "")
{
var sql = $"select {{0}}{Environment.NewLine}from {sqlGenerate.TableName}";
string fields = "";
if (expression == null)
{
var dbType = sqlGenerate.DatabaseType;
var pis = typeof(T).GetProperties();
foreach (var pi in pis)
{
string fieldName = pi.GetFieldName();
if (string.IsNullOrEmpty(fieldName))
{
continue;
}
fields += $"{fieldName.ParamSql(dbType)} as {pi.Name.ParamSql(dbType)},";
}
fields = fields.TrimEnd(',');
}
else
{
SqlExpressionProvider.Select(expression, sqlGenerate);
fields = sqlGenerate.SelectFieldsStr;
}
sqlGenerate.Sql.AppendFormat(sql, fields);
return(this);
}
protected override SqlGenerate Select(UnaryExpression expression, SqlGenerate sqlGenerate)
{
SqlExpressionProvider.Select(expression.Operand, sqlGenerate);
return(sqlGenerate);
}
protected override SqlGenerate Select(LambdaExpression expression, SqlGenerate sqlGenerate)
{
SqlExpressionProvider.Select(expression.Body, sqlGenerate);
return(sqlGenerate);
}