大约有 42,000 项符合查询结果（耗时：0.0335秒） [XML]
string.IsNullOrEmpty(string) vs. string.IsNullOrWhiteSpace(string)
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The best practice is selecting the most appropriate one.
.Net Framework 4.0 Beta 2 has a new IsNullOrWhiteSpace() method for
strings which generalizes the IsNullOrEmpty() method to also include other white
space besides empty string.
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How to concatenate columns in a Postgres SELECT?
... an explicit coercion to text [...]
Bold emphasis mine. The 2nd example (select a||', '||b from foo) works for any data types since the untyped string literal ', ' defaults to type text making the whole expression valid in any case.
For non-string data types, you can "fix" the 1st statement by c...
How do I list all the columns in a table?
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For Oracle (PL/SQL)
SELECT column_name
FROM user_tab_cols
WHERE table_name = 'myTableName'
For MySQL
SHOW COLUMNS FROM table_name
share
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i...
MySQL Conditional Insert
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If your DBMS does not impose limitations on which table you select from when you execute an insert, try:
INSERT INTO x_table(instance, user, item)
SELECT 919191, 123, 456
FROM dual
WHERE NOT EXISTS (SELECT * FROM x_table
WHERE user = ...
Concatenate multiple result rows of one column into one, group by another column [duplicate]
...Simpler with the aggregate function string_agg() (Postgres 9.0 or later):
SELECT movie, string_agg(actor, ', ') AS actor_list
FROM tbl
GROUP BY 1;
The 1 in GROUP BY 1 is a positional reference and a shortcut for GROUP BY movie in this case.
string_agg() expects data type text as input. Other ...
Is there any connection string parser in C#?
...here(kvp => kvp.Contains('='))
.Select(kvp => kvp.Split(new char[] { '=' }, 2))
.ToDictionary(kvp => kvp[0].Trim(),
kvp => kvp[1].Trim(),
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SQL: capitalize first letter only [duplicate]
...t only for displaying and do not need the actual data in table to change:
SELECT UPPER(LEFT(word,1))+LOWER(SUBSTRING(word,2,LEN(word))) FROM [yourtable]
Hope this helps.
EDIT: I realised about the '-' so here is my attempt to solve this problem in a function.
CREATE FUNCTION [dbo].[CapitalizeFi...
What is the direction of stack growth in most modern systems?
... else's code.
The processors and their direction are:
x86: down.
SPARC: selectable. The standard ABI uses down.
PPC: down, I think.
System z: in a linked list, I kid you not (but still down, at least for zLinux).
ARM: selectable, but Thumb2 has compact encodings only for down (LDMIA = increment ...
How do I find a stored procedure containing ?
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SELECT ROUTINE_NAME, ROUTINE_DEFINITION
FROM INFORMATION_SCHEMA.ROUTINES
WHERE ROUTINE_DEFINITION LIKE '%Foo%'
AND ROUTINE_TYPE='PROCEDURE'
SELECT OBJECT_NAME(id)
FROM SYSCOMMENTS
WHERE [text] LIKE...
How to split a file into equal parts, without breaking individual lines? [duplicate]
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this is a way better answer than the selected one
– smatthewenglish
Apr 28 '16 at 11:41
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