where

问题 Let's say I have the following model: class Movie extends Eloquent { public function director() { return $this->belongsTo('Director'); } } Now I'd like fetch movies using a where condition that's based on a column from the directors table. Is there a way to achieve this? Couldn't find any documentation on conditions based on a belongs to relationship. 回答1: You may try this (Check Querying Relations on Laravel website): $movies = Movie::whereHas('director', function($q) { $q->where('name',

问题 Let's say I have the following model: class Movie extends Eloquent { public function director() { return $this->belongsTo('Director'); } } Now I'd like fetch movies using a where condition that's based on a column from the directors table. Is there a way to achieve this? Couldn't find any documentation on conditions based on a belongs to relationship. 回答1: You may try this (Check Querying Relations on Laravel website): $movies = Movie::whereHas('director', function($q) { $q->where('name',

问题 The Swift documentation at page 61 of the Swift manual hints to the possibility of using where to join an optional binding with a regular condition. Yet when I do it I have a warning suggesting me to substitute the where with a comma like in the following piece of code: if let geocodingError = error as? NSError where geocodingError.code == 2 回答1: Example with two conditions if let x = y, let a = b, a == x && !x.isEmpty { 回答2: In Swift 3 this syntax has changed. What was if let x = y, a = b

问题 How can I add a sub where statement in SQL if my Boolean parameter is true in JasperReports ? For example, I have my SQL as below: SELECT * FROM shops WHERE region = "Canada" ORDER BY name If my parameter is true, I would like to add and isactive = 'Y' just before ORDER BY . Anybody knows how I can achieve this? 回答1: You can add additional parameter for setting additional clause value. After that you can use $P!{} syntax in query. The sample: <parameter name="param" class="java.lang.Boolean"/

问题 I want to be able to select only the field where a certain field contains both letters and numbers. for example: Select [field1], [field2] from [db1].[table1] where [field2] = *LETTERS AND NUMBERS* Im using SQL Server 2005, also im sorry bu im not a hundred percent sure about the data type of the field because it is on a linked server and un-accessibleat the minute. Hope you can help :) 回答1: LIKE will do it. This is a double negative where [field2] NOT LIKE '%[^0-9a-z]%' It says: %[^0-9a-z]%

问题 This question already has an answer here : Bind multiple parameters into mysqli query (1 answer) Closed 3 years ago . I've looked all over the internet for answers on this one, and prepared statements and bind params come up (I have no idea what that stuff is) Basically, I have a comma separated list $list = 'food, drink, cooking'; Ok, now I want to search for each of those items in a column of the database... Sounds simple, right? $query = "SELECT * FROM table WHERE stuff IN ('$list')";

问题 In SQL I am trying to filter results based on an ID and wondering if there is any logical difference between SELECT value FROM table1 JOIN table2 ON table1.id = table2.id WHERE table1.id = 1 and SELECT value FROM table1 JOIN table2 ON table1.id = table2.id AND table1.id = 1 To me, it seems as if the logic is different though you will always get the same set of results but I wondered if there were any conditions under which you would get two different result sets (or would they always return

问题 Anyone know any speed differences between Where and FindAll on List. I know Where is part of IEnumerable and FindAll is part of List, I'm just curious what's faster. 回答1: The FindAll method of the List<T> class actually constructs a new list object, and adds results to it. The Where extension method for IEnumerable<T> will simply iterate over an existing list and yield an enumeration of the matching results without creating or adding anything (other than the enumerator itself.) Given a small

问题 The Select and Where methods are available in Linq. What should every developer know about these two methods? For example: when to use one over the other, any advantages of using one over the other, etc. 回答1: Where finds items that match and only returns those that do ( filtering ). -> IEnumerable<A> in, IEnumerable<A> out Select returns something for all items in the source ( projection / transformation ). That something might be the items themselves, but are more usually a projection of

问题 I do have some courses, to which students can enroll. There's a users table (usuarios), a courses (cursos) table and a third table that shows each student enrollment (cursosUsuarios), like this: CREATE TABLE usuarios( userID int unsigned not null auto_increment primary key, userName char(50) null, )ENGINE=InnoDB DEFAULT CHARSET=utf8; CREATE TABLE cursos ( cursoID int unsigned not null auto_increment primary key, nombreCurso char(100) not null, estadoCurso char(50) not null, )ENGINE=InnoDB