exists Questions
6
Solved
How I can check existing property $this->team->playerAssignment->player in more rational way? Now I check it like this:
if ($this->team)
if (($this->team->playerAssignment))
if...
Poucher asked 19/9, 2017 at 13:21
6
Solved
I can check that a function exists in my environment:
> exists("is.zoo")
[1] FALSE
I can check that a function exists after loading a package by loading it:
> library(zoo)
> exists("...
6
Solved
How do I check if a particular element exists in a table - how can I return true or false?
I have a table that has
user_id
user_password
user_secretQ
Verbally, I want to do this: If a particu...
Garlicky asked 4/11, 2010 at 16:22
2
I wrote query
select * from table
where exists (select 1 from table1 where table.column = table1.column)
If i will change it to
select * from table
where exists (select 1 from table1 where ta...
Cairn asked 6/6, 2016 at 14:42
5
I am trying to update a selected values in a column in a SQLite table. I only want update of the cells in the maintable where the criteria are met, and the cells must be updated to individual value...
Kreutzer asked 6/6, 2012 at 19:51
5
Solved
In the following JSON response, what's the proper way to check if the nested key "C" exists in python 2.7?
{
"A": {
"B": {
"C": {"D": "yes"}
}
}
}
one line JSON
{ "A": { "B": { "C": {"D": ...
Desireedesiri asked 4/3, 2013 at 0:17
8
Declare @CategoryID as int
BEGIN
SELECT
(CASE
WHEN EXISTS(
SELECT t0.Categoryid AS [EMPTY]
FROM Categories AS [t0]
WHERE [t0].Categoryname = @CategoryName
) THEN 1
ELSE 0
END) AS [value...
Candidate asked 11/3, 2014 at 9:39
3
In delphi XE, when I call SysUtils DirectoryExists function with the following input
'Y:\blabla\'
where Y is a network mapped unit, it correctly returns false because blabla doesnt exist.
But wh...
4
Solved
Is there any performance benefit in adding a LIMIT to an EXISTS query, or would MySQL apply the limit on its own?
Example:
IF EXISTS (
SELECT 1
FROM my_table
LIMIT 1 -- can this improve perfor...
Vitalize asked 13/1, 2016 at 5:41
25
Solved
Is it possible to check if a (MySQL) database exists after having made a connection.
I know how to check if a table exists in a DB, but I need to check if the DB exists. If not I have to call anot...
5
Solved
I am new to Python, and I am trying to check whether a pair [a,b] exists in a list l=[[a,b],[c,d],[d,e]]. I searched many questions, but couldn't find precise solution. Please can someone tell me t...
7
How do I check whether data in a query exists?
For example:
users_query = User.query.filter_by(email='[email protected]')
How I can check whether users with that email exist?
I can check ...
Rubenrubens asked 4/10, 2011 at 10:0
22
What is the difference between the EXISTS and IN clause in SQL?
When should we use EXISTS, and when should we use IN?
16
Solved
An alternative title might be:
Check for existence of multiple rows?
Using a combination of SQL and C# I want a method to return true if all products in a list exist in a table. If it can be done ...
Crypto asked 19/5, 2010 at 0:23
34
I changed the datadir of a MySQL installation and all the bases moved correctly except for one.
I can connect and USE the database. SHOW TABLES also returns me all the tables correctly, and the fi...
Cargian asked 13/10, 2011 at 19:7
2
Solved
I have a database split in FrontEnd and BackEnd.
I have it running:
i) in my office
ii) updating/testing in my personal computer.
My BackEnd file is running in different Folder location according...
3
A part of my test includes a table where user's can add or delete rows.
I cannot control if the table will be empty or not, so I need to have conditionals if to find out if the table is empty...
Rosina asked 1/6, 2020 at 18:49
9
Solved
So, I have a script that adds extended properties, some describing a table, some describing a column. How can I check if the extended property exists before adding it so that the script does not th...
Osprey asked 18/6, 2013 at 15:44
7
Solved
I want to check if a row exists in a database table or not. I first used this approach:
type MyStruct struct {
ID uint32
Key string
Value string
}
var result MyStruct
err := db.
Where("i...
4
Solved
Say I have a set of rules that have a validation function that returns IO[Boolean] at runtime.
case class Rule1() {
def validate(): IO[Boolean] = IO.pure(false)
}
case class Rule2() {
def validat...
Tort asked 4/12, 2022 at 14:47
10
Solved
I have this code. It is supposed to check if a file exists and open it if it does. It does work if the file exists, and if it doesn't, however, whenever I leave the textbox blank and click the subm...
Cyrille asked 3/5, 2013 at 3:43
5
Solved
How to select Boolean value from sub query with IF EXISTS statement (SQL Server)?
It should be something like :
SELECT
TABLE1.Id,
NewFiled = (IF EXISTS(SELECT Id FROM TABLE2 WHERE TABLE2.ID = T...
Ossuary asked 18/10, 2011 at 9:20
10
Solved
Suppose I have this table:
id | name | city
------------------
1 | n1 | c1
2 | n2 | c2
3 | n3 | c3
4 | n4 | c4
I want to check if the value c7 exists under the variable city or not.
If it does...
2
Solved
I'm trying to write a simple function in javascript to check if an element exists in the DOM and if it does remove, and if it doesn't, append it to the page, so far i've got this
if document.cont...
Furthest asked 5/2, 2014 at 23:56
8
Solved
In my app a User can create a Business. When they trigger the index action in my BusinessesController I want to check if a Business is related to the current_user.id:
If yes: display the business...
Ko asked 22/5, 2013 at 2:49
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