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MySQL - Rows to Columns
...you need to pivot is to let mysql build the query for you:
SELECT
GROUP_CONCAT(DISTINCT
CONCAT(
'ifnull(SUM(case when itemname = ''',
itemname,
''' then itemvalue end),0) AS `',
itemname, '`'
)
) INTO @sql
FROM
history;
SET @sql = CONCAT('SELECT hostid, ', @sql...
String Concatenation using '+' operator
... see the operators == and != overloaded. So how is it able to perform concatenation for the ' + ' operator?
1 Answer
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Apply pandas function to column to create multiple new columns?
...3 1.100880 -0.899120
4 1.017859 -0.982141
Editing for completeness
pd.concat([df, df.textcol.apply(lambda s: pd.Series({'feature1':s+1, 'feature2':s-1}))], axis=1)
textcol feature1 feature2
0 0.626524 1.626524 -0.373476
1 0.119967 1.119967 -0.880033
2 0.803650 1.803650 -0.196350
3 0.10...
XDocument.ToString() drops XML Encoding Tag
...
use this:
output.Text = String.Concat(xml.Declaration.ToString() , xml.ToString())
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How do I read the contents of a Node.js stream into a string variable?
... stream.on('error', reject)
stream.on('end', () => resolve(Buffer.concat(chunks).toString('utf8')))
})
}
const result = await streamToString(stream)
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...
Extract numbers from a string
...ul with this method: something like 'In My Car_Price : 500.00 will print : 50000
– ErickBest
Jul 22 '13 at 10:10
20
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What's the best name for a non-mutating “add” method on an immutable collection?
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In situations like that, I usually go with Concat. That usually implies to me that a new object is being created.
var p = listA.Concat(listB);
var k = listA.Concat(item);
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How do you debug MySQL stored procedures?
..._msg(enabled INTEGER, msg VARCHAR(255))
BEGIN
IF enabled THEN
select concat('** ', msg) AS '** DEBUG:';
END IF;
END $$
CREATE PROCEDURE test_procedure(arg1 INTEGER, arg2 INTEGER)
BEGIN
SET @enabled = TRUE;
call debug_msg(@enabled, 'my first debug message');
call debug_msg(@enabled, (...
In MySQL, can I copy one row to insert into the same table?
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SET @temptable = '_duplicate_temp_table';
SET @sql_text = CONCAT('CREATE TABLE ', @temptable, ' LIKE ', copytable);
PREPARE stmt FROM @sql_text;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
SET @sql_text = CONCAT('INSERT INTO ', @temptable, ' SELECT * FROM ...
List of strings to one string
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String.Join in conjunction with String.Concat is golden. Ex: 'String.Concat( "{ ", String.Join( ", ", m_Data ), " }" );'
– KornMuffin
Oct 21 '11 at 16:01
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