大约有 47,000 项符合查询结果（耗时：0.0385秒） [XML]
MySQL combine two columns into one column
...does not start with a digit, then the converted value is 0.
So try this:
select concat(column1, column2)
Two ways to add a space:
select concat(column1, ' ', column2)
select concat_ws(' ', column1, column2)
share
...
Fetch the row which has the Max value for a column
... multiple rows for the userid where the maximum date is on multiple rows.
select userid,
my_date,
...
from
(
select userid,
my_date,
...
max(my_date) over (partition by userid) max_my_date
from users
)
where my_date = max_my_date
"Analytic functions rock"
Edi...
Getting a 404 from WMSvc via MSDeploy.exe
...el > Programs and Features. Right-click "Microsoft Web Deploy 3.5" and select "Change". From the installer select "Change" and "IIS Deployment Handler" was available as an option (was disabled at first. Also "Configure for Non-Administrator Deployments" and "Management Service Delegation UI" w...
How to list the tables in a SQLite database file that was opened with ATTACH?
...quently, if you used
ATTACH some_file.db AS my_db;
then you need to do
SELECT name FROM my_db.sqlite_master WHERE type='table';
Note that temporary tables don't show up with .tables either: you have to list sqlite_temp_master for that:
SELECT name FROM sqlite_temp_master WHERE type='table';
...
Get first day of week in SQL Server
...in that there should be some sensible logic built in to round up or down:
SELECT DATEDIFF(YEAR, '2010-01-01', '2011-12-31');
SELECT DATEDIFF(YEAR, '2010-12-31', '2011-01-01');
To answer how to get a Sunday:
If you want a Sunday, then pick a base date that's not a Monday but rather a Sunday. For ...
select into in mysql
...
Use the CREATE TABLE SELECT syntax.
http://dev.mysql.com/doc/refman/5.0/en/create-table-select.html
CREATE TABLE new_tbl SELECT * FROM orig_tbl;
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How to do a case sensitive search in WHERE clause (I'm using SQL Server)?
...the Collation. By default it is case insensitive.
Excerpt from the link:
SELECT 1
FROM dbo.Customers
WHERE CustID = @CustID COLLATE SQL_Latin1_General_CP1_CS_AS
AND CustPassword = @CustPassword COLLATE SQL_Latin1_General_CP1_CS_AS
Or, change the columns to be case sensitive.
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How does one reorder columns in a data frame?
...
You can also use the subset function:
data <- subset(data, select=c(3,2,1))
You should better use the [] operator as in the other answers, but it may be useful to know that you can do a subset and a column reorder operation in a single command.
Update:
You can also use the select...
Find all tables containing column with specified name - MS SQL Server
...
Search Tables:
SELECT c.name AS 'ColumnName'
,t.name AS 'TableName'
FROM sys.columns c
JOIN sys.tables t ON c.object_id = t.object_id
WHERE c.name LIKE '%MyName%'
ORDER BY TableName
,C...
Group by in LINQ
... p in persons
group p.car by p.PersonId into g
select new { PersonId = g.Key, Cars = g.ToList() };
Or as a non-query expression:
var results = persons.GroupBy(
p => p.PersonId,
p => p.car,
(key, g) => new { PersonId = key, Cars = g.ToList() });
...