大约有 48,000 项符合查询结果（耗时：0.0266秒） [XML]
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...
SQL Server: Get data for only the past year
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The following adds -1 years to the current date:
SELECT ... From ... WHERE date > DATEADD(year,-1,GETDATE())
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follo...
What is the difference between ExecuteScalar, ExecuteReader and ExecuteNonQuery?
... then the result is the first column of the first row. An example might be SELECT @@IDENTITY AS 'Identity'.
ExecuteReader is used for any result set with multiple rows/columns (e.g., SELECT col1, col2 from sometable).
ExecuteNonQuery is typically used for SQL statements without results (e.g., UPDATE...
django models selecting single field
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thanks for the answer, what if I want to select only 1 or more fields (not all)?
– zentenk
Sep 21 '11 at 16:42
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How to 'insert if not exists' in MySQL?
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Solution:
INSERT INTO `table` (`value1`, `value2`)
SELECT 'stuff for value1', 'stuff for value2' FROM DUAL
WHERE NOT EXISTS (SELECT * FROM `table`
WHERE `value1`='stuff for value1' AND `value2`='stuff for value2' LIMIT 1)
Explanation:
The innermost query
SELECT *...
Check if all checkboxes are selected
How do I check if all checkboxes with class="abc" are selected?
9 Answers
9
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Run all SQL files in a directory
...o and make sure SQLCMD Mode is enabled
Click on SQLCMD Mode; files will be selected in grey as below
:r c:\Scripts\script1.sql
:r c:\Scripts\script2.sql
:r c:\Scripts\script3.sql
Now execute
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LINQPad [extension] methods [closed]
...QueryLanguage.Expression, @"from c in Customers
where c.Name.Length > 3
select c.Name", "Click to run!").Dump();
You can also write your own extension methods in LINQPad. Go to 'My Queries' and click the query called 'My Extensions'. Any types/methods that define here are accessible to all quer...
How to perform Single click checkbox selection in WPF DataGrid?
...ck the check box. It should get checked.
But, it takes two click to get selected, for first click the cell is getting selected, for the second clicks the check box is getting checked. How to make the check box to get checked/unchecked with a single click.
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How to find a hash key containing a matching value
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You could use Enumerable#select:
clients.select{|key, hash| hash["client_id"] == "2180" }
#=> [["orange", {"client_id"=>"2180"}]]
Note that the result will be an array of all the matching values, where each is an array of the key and value.
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