大约有 44,000 项符合查询结果（耗时：0.0237秒） [XML]
Detect if value is number in MySQL
...
This should work in most cases.
SELECT * FROM myTable WHERE concat('',col1 * 1) = col1
It doesn't work for non-standard numbers like
1e4
1.2e5
123. (trailing decimal)
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How do I check if an index exists on a table field in MySQL?
... b.table_type = 'BASE TABLE'
left join (
select concat(x.name, '/', y.name) full_path_schema, y.name index_name
FROM information_schema.INNODB_SYS_TABLES as x
JOIN information_schema.INNODB_SYS_INDEXES as y on x.TABLE_ID = y.TABLE_ID
WHERE x.name = 'your_schema'
...
What purpose does a tag serve inside of a tag?
... systemPage = js;
} else if (key) {
others = others.concat(js);
} else {
inline = inline.concat(js);
}
}
}
for (var i = 0; i < scripts.length; s++) {
var script = scripts[i];
var src = script.src;
if (!isListed(src...
Can I “multiply” a string (in C#)?
...
In .NET 4 you can do this:
String.Concat(Enumerable.Repeat("Hello", 4))
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How to combine paths in Java?
...oes have a class FilenameUtils that can do this kind of thing, such as the concat() method.
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JavaScript variable number of arguments to function
...rty. This includes the arguments object. Knowing this, and that the method concat returns a copy of the 'array' it's called on, we can easily convert the arguments object to a real array like this: var args = [].concat.call(arguments). Some people prefer to use Array.prototype.concat.call instead, b...
GROUP BY with MAX(DATE) [duplicate]
...t try this...
SELECT
`Train`,
`Dest`,
SUBSTRING_INDEX(GROUP_CONCAT(`Time` ORDER BY `Time` DESC), ",", 1) AS `Time`
FROM TrainTable
GROUP BY Train;
Src: Group Concat Documentation
Edit: fixed sql syntax
shar...
Creating an empty Pandas DataFrame, then filling it?
...ire handling the index appropriately).
Things you should NOT do
append or concat inside a loop
Here is the biggest mistake I've seen from beginners:
df = pd.DataFrame(columns=['A', 'B', 'C'])
for a, b, c in some_function_that_yields_data():
df = df.append({'A': i, 'B': b, 'C': c}, ignore_index=...
Pandas groupby: How to get a union of strings
...is!
3 3 0.463468 a
4 4 0.643961 random
sum by default concatenates
In [9]: df.groupby('A')['C'].apply(lambda x: x.sum())
Out[9]:
A
1 Thisstring
2 is!
3 a
4 random
dtype: object
You can do pretty much what you want
In [11]: df.groupby('A')['C'...
How do I create a PDO parameterized query with a LIKE statement?
...e LIKE with % partial matching for MySQL databases: WHERE column_name LIKE CONCAT('%', :dangerousstring, '%')
where the named parameter is :dangerousstring.
In other words, use explicitly unescaped % signs in your own query that are separated and definitely not the user input.
Edit: Concatenati...