distinct

问题 I have two MySQL tables (product and price history) that I would like to join: Product table: Id = int Name = varchar Manufacturer = varchar UPC = varchar Date_added = datetime Price_h table: Id = int Product_id = int Price = int Date = datetime I can perform a simple LEFT JOIN: SELECT Product.UPC, Product.Name, Price_h.Price, Price_h.Date FROM Product LEFT JOIN Price_h ON Product.Id = Price_h.Product_id; But as expected if I have more than one entry for a product in the price history table,

问题 hi guy i have a query that give me the followin error: ORA-01791: not a SELECTed expression this is the select expresison , please can you tell me why ? declare freqLettura varchar2(64); billingcy varchar2(64); begin freqLettura := null; billingcy := null; for rec in ( select distinct(fn_get_facilityid(z.uidfacility) ) as a, 1 as b from facilityhistory z, locality l , plant p , ztmp_sam_tb_sdv zsdv , ztmp_sam_tb_plantcode zplant , sam_tb_ca_pdr sam, meterhistory mh, meter m , meterclass mc

问题 As per the title, what would be the PHP Mongo equivalent of something like this in SQL: SELECT DISTINCT(field) FROM table WHERE someCondition = 1 I've read looked at this table but I don't see how to map db.users.distinct('last_name') into PHP. 回答1: Just issue a command and set the distinct key. Take a look at the following example from the docs: Finding all of the distinct values for a key. <?php $people = $db->people; $people->insert(array("name" => "Joe", "age" => 4)); $people->insert

问题 Here is the Select I need to convert to an Update: SELECT DISTINCT f.SectionID, f.Name, v.Enabled FROM SETTING_VALUE v INNER JOIN SETTING s ON v.SettingID = s.SettingID INNER JOIN LU_FIELD f ON f.FieldID = s.FieldID WHERE v.DisplayValue LIKE '%Miami%' AND f.ControlName LIKE '%City%' My attempt: UPDATE SETTING_VALUE SET Enabled = 0 FROM SETTING_VALUE v INNER JOIN SETTING s ON v.SettingID = s.SettingID INNER JOIN LU_FIELD f ON f.FieldID = s.FieldID WHERE v.DisplayValue LIKE '%Miami%' AND f

问题 Here is the Select I need to convert to an Update: SELECT DISTINCT f.SectionID, f.Name, v.Enabled FROM SETTING_VALUE v INNER JOIN SETTING s ON v.SettingID = s.SettingID INNER JOIN LU_FIELD f ON f.FieldID = s.FieldID WHERE v.DisplayValue LIKE '%Miami%' AND f.ControlName LIKE '%City%' My attempt: UPDATE SETTING_VALUE SET Enabled = 0 FROM SETTING_VALUE v INNER JOIN SETTING s ON v.SettingID = s.SettingID INNER JOIN LU_FIELD f ON f.FieldID = s.FieldID WHERE v.DisplayValue LIKE '%Miami%' AND f

问题 I don't know how I can do several union with a distinct. When I use .Distinct with an IEqualityComparer an exception in threw : LINQ to Entities does not recognize the method 'System.Linq.IQueryable' My code is var union = query.Union(query1).Union(query2); union = union.Distinct(new EqualityComparerTransaction()); 回答1: LINQ to Entities does not support the overload of Distinct which takes an IEqualityComparer . When you think about it, it really can't, because LINQ to Entities queries will

问题 I understand this is just a very simple question and most likely have been answered somewhere, but as a beginner I still don't get it and am looking for your enlightenment, thank you in advance: I have a interim dataframe: +----------------------------+---+ |host |day| +----------------------------+---+ |in24.inetnebr.com |1 | |uplherc.upl.com |1 | |uplherc.upl.com |1 | |uplherc.upl.com |1 | |uplherc.upl.com |1 | |ix-esc-ca2-07.ix.netcom.com |1 | |uplherc.upl.com |1 | What I need is to remove

问题 I use Xml.Linq for manage xml configuration files. I have XElement (Company.CalidadCodigo.ParserSQL.Reglas), and I need remove duplicate values in XElement (nodes Add-Key-Value, which Value is repeated). I use Union but not right. var reglasComunes = reglasParaTarget.Union(reglasParaSecundario); Any sample code about it? <?xml version="1.0" encoding="utf-8"?> <configuration> <configSections> <section name="Company.CalidadCodigo.ParserSQL.Reglas" type="System.Configuration

问题 I've got the following classes: public class SupplierCategory : IEquatable<SupplierCategory> { public string Name { get; set; } public string Parent { get; set; } #region IEquatable<SupplierCategory> Members public bool Equals(SupplierCategory other) { return this.Name == other.Name && this.Parent == other.Parent; } #endregion } public class CategoryPathComparer : IEqualityComparer<List<SupplierCategory>> { #region IEqualityComparer<List<SupplierCategory>> Members public bool Equals(List

问题 I've got this test HQL: select distinct o from Order o left join fetch o.lineItems and it does generate an SQL distinct without an obvious reason: select distinct order0_.id as id61_0_, orderline1_.order_id as order1_62_1_... The SQL resultset is always the same (with and without an SQL distinct): order id | order name | orderline id | orderline name ---------+------------+--------------+--------------- 1 | foo | 1 | foo item 1 | foo | 2 | bar item 1 | foo | 3 | test item 2 | empty | NULL |