大约有 47,000 项符合查询结果（耗时：0.0714秒） [XML]
Which SQL query is faster? Filter on Join criteria or Where clause?
...INNER JOIN with a LEFT JOIN.
In your very case this will look like this:
SELECT *
FROM TableA a
LEFT JOIN
TableXRef x
ON x.TableAID = a.ID
AND a.ID = 1
LEFT JOIN
TableB b
ON x.TableBID = b.ID
or this:
SELECT *
FROM TableA a
LEFT JOIN
TableXRef x...
Is there a standard keyboard shortcut to build the current project in Visual Studio?
...mmand doesn't seem to work in VS2008.
Assign the shortcut to "Build.BuildSelection". If you have a solution with several projects and files open from the various projects, whatever file you are currently editing will define the project that will be built when you use the assigned shortcut for "Bu...
Visual Studio: How can I see the same file in two separate tab groups?
...have two copies of the same file. Then you can right-click the tab bar and select New Vertical Tab Group (or New Horizontal Tab Group, the one you like more).
Hope I understood you question..
share
|
...
Ora-00257 错误处理一列 - 数据库(内核) - 清泛网 - 专注C/C++及内核技术
.../oracle/.bash_profile
进入ORLACE
sqlplus /as sysdba
SQL> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES BLOCKSIZE MEMBERS ARC
---------- ---------- ---------- ---------- ---------- ---------- ---
STATUS FIRST_CHANGE# FIRST_TIME NEXT_CHANGE#...
SQL WHERE condition is not equal to?
... clause may be negated according to the above rules. The negation of this
select *
from foo
where test-1
and test-2
and ( test-3
OR test-4
)
is
select *
from foo
where NOT( test-1
and test-2
and ( test-3
OR te...
How do I escape a single quote in SQL Server?
...lue] VARCHAR(200)
)
INSERT INTO @my_table VALUES ('hi, my name''s tim.')
SELECT * FROM @my_table
Results
value
==================
hi, my name's tim.
share
|
improve this answer
|
...
XPath - Selecting elements that equal a value
In Xpath, I am wanting to select elements that equal a specific value.
2 Answers
2
...
Which data type for latitude and longitude?
...e using gist (geog);
and then request, say, 5 closest to a given point:
select *
from your_table
order by geog <-> 'SRID=4326;POINT(lon lat)'
limit 5;
share
|
improve this answer
...
Oracle 11.2.0.4 RAC FOR redhat 6.4 - 数据库(内核) - 清泛网 - 专注C/C++及内核技术
...nolog
SQL> conn / as sysdba
SQL> startup
查看数据库状态
SQL> select open_mode from v$database;
OPEN_MODE
--------------------
READ WRITE
查看数据库字符集
SQL> select userenv('language') from dual;
SQL> select * from props$ where name='NLS_CHARACTERSET';
SQL> select * ...
Repeat each row of data.frame the number of times specified in a column
...es
library(dplyr)
df %>%
slice(rep(seq_len(n()), freq)) %>%
select(-freq)
# var1 var2
#1 a d
#2 b e
#3 b e
#4 c f
#5 c f
#6 c f
seq_len(n()) part can be replaced with any of the following.
df %>% slice(rep(1:nrow(df), freq)) %>% select(-...