大约有 40,000 项符合查询结果（耗时：0.0262秒） [XML]
How to remove leading and trailing whitespace in a MySQL field?
...d the use case before using this solution:
trim does not work while doing select query
This works
select replace(name , ' ','') from test;
While this doesn't
select trim(name) from test;
share
|
...
Is there a REAL performance difference between INT and VARCHAR primary keys?
...a decent programming background but my SQL experience is limited mostly to SELECT queries
– Rob
Jul 3 '12 at 14:47
...
Oracle Differences between NVL and Coalesce
...the first non-NULL (there are some exceptions, such as sequence NEXTVAL):
SELECT SUM(val)
FROM (
SELECT NVL(1, LENGTH(RAWTOHEX(SYS_GUID()))) AS val
FROM dual
CONNECT BY
level <= 10000
)
This runs for almost 0.5 seconds, since it generates...
What are Aggregates and PODs and how/why are they special?
...ns (10.3) and no virtual base classes (10.1), and
— the constructor selected to copy/move each direct base class subobject is trivial, and
— for each non-static data member of X that is of class type (or array thereof), the constructor
selected to copy/move that member is trivial;
...
Oracle nvarchar和varchar相互转换、联合查询 - 数据库(内核) - 清泛网 - ...
...tatype isNVARCHAR2.
（A表字段c_xxx:varchar，B表c_xxx:nvarchar）
select translate(c_xxx USING NCHAR_CS) from A
union all
select c_xxx from B
或者
select c_xxx from A
union all
select translate(c_xxx USING CHAR_CS) from B
注意：translate函数括号中没有逗号。
1、...
Is gcc's __attribute__((packed)) / #pragma pack unsafe?
...option, enabled by default.
When address of packed member of struct or union is taken, it may
result in an unaligned pointer value. This patch adds
-Waddress-of-packed-member to check alignment at pointer assignment and warn unaligned address as well as unaligned pointer
I've just built t...
Turning a Comma Separated string into individual rows
... SomeID INT,
OtherID INT,
String VARCHAR(MAX)
)
INSERT Testdata SELECT 1, 9, '18,20,22'
INSERT Testdata SELECT 2, 8, '17,19'
INSERT Testdata SELECT 3, 7, '13,19,20'
INSERT Testdata SELECT 4, 6, ''
INSERT Testdata SELECT 9, 11, '1,2,3,4'
The query
;WITH tmp(SomeID, OtherID, DataIt...
What are the mechanics of short string optimization in libc++?
...of(__long) - 1)/sizeof(value_type) : 2};
struct __short
{
union
{
unsigned char __size_;
value_type __lx;
};
value_type __data_[__min_cap];
};
union __ulx{__long __lx; __short __lxx;};
enum {__n_words = sizeof(__ulx) / si...
Number of rows affected by an UPDATE in PL/SQL
... block, this can be achieved.
... If anyone has a solution to use it in a SELECT Command, I would be interested.
share
|
improve this answer
|
follow
|
...
nvarchar和varchar相互转换、联合查询 - ORACLE - 清泛IT论坛，有思想、有深度
...atype is NVARCHAR2.
（A表字段c_xxx:varchar，B表c_xxx:nvarchar）
select translate(c_xxx USING NCHAR_CS) from A
union all
select c_xxx from B
或者
select c_xxx from A
union all
select translate(c_xxx USING CHAR_CS) from B
注意：translate函数括号中没有逗号。
1、...