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Error while installing json gem 'mkmf.rb can't find header files for ruby'
...installing command-line tools and accepting the license with
sudo xcode-select --install
sudo xcodebuild -license accept
The issue is that Xcode 11 ships the macOS 10.15 SDK which includes headers for ruby2.6, but not for macOS 10.14's ruby2.3. You can verify that this is your problem by runnin...
CASCADE DELETE just once
...you want to cascade.
DELETE FROM some_child_table WHERE some_fk_field IN (SELECT some_id FROM some_Table);
DELETE FROM some_table;
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Selecting pandas column by location
...ed in future versions. See pandas.pydata.org/pandas-docs/dev/… on how to select by position using iloc/iat.
– Wouter Overmeire
Apr 12 '13 at 10:04
1
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Selecting an element in iFrame jQuery
...rame. All the elements in that loaded page have their tokenid-s. I need to select the elements by those tokenid-s. Means - I click on an element on the main page and select corresponding element in the page in the iFrame. With the help of jQuery I'm doing it in the following way:
...
CSS Child vs Descendant selectors
I am a bit confused between these 2 selectors.
8 Answers
8
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How to check SQL Server version
... Connect to the instance of SQL Server, and then run the following query:
Select @@version
An example of the output of this query is as follows:
Microsoft SQL Server 2008 (SP1) - 10.0.2531.0 (X64) Mar 29 2009
10:11:52 Copyright (c) 1988-2008 Microsoft Corporation Express
Edition (64-bit) ...
c# datatable to csv
...s = dt.Columns.Cast<DataColumn>().
Select(column => column.ColumnName).
ToArray();
sb.AppendLine(string.Join(",", columnNames));
foreach (DataRow row in dt.Rows)
{
string[] fields = row.ItemArray.Select(field => fie...
Retrieve column names from java.sql.ResultSet
... metadata. See ResultSetMetaData
e.g.
ResultSet rs = stmt.executeQuery("SELECT a, b, c FROM TABLE2");
ResultSetMetaData rsmd = rs.getMetaData();
String name = rsmd.getColumnName(1);
and you can get the column name from there. If you do
select x as y from table
then rsmd.getColumnLabel() wi...
Linq to Entities join vs groupjoin
...Join syntax would be
from p in Parent
join c in Child on p.Id equals c.Id
select new { p.Value, c.ChildValue }
returning an IEnumerable<X> where X is an anonymous type with two properties, Value and ChildValue. This query syntax uses the Join method under the hood.
GroupJoin syntax would be
...
SQL query for finding records where count > 1
...ers that have more than one payment per day with the same account number
SELECT
user_id ,
COUNT(*) count
FROM
PAYMENT
GROUP BY
account,
user_id ,
date
Having
COUNT(*) > 1
Update
If you want to only include those that have a distinct ZIP you can get a distinct set first and then perfor...