大约有 40,000 项符合查询结果（耗时：0.0330秒） [XML]
How to select the row with the maximum value in each group
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Here's a data.table solution:
require(data.table) ## 1.9.2
group <- as.data.table(group)
If you want to keep all the entries corresponding to max values of pt within each group:
group[group[, .I[pt == max(pt)], by=Subject]$V1]
# ...
Store boolean value in SQLite
What is the type for a BOOL value in SQLite? I want to store in my table TRUE/FALSE values.
8 Answers
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What MySQL data type should be used for Latitude/Longitude with 8 decimal places?
...types and Point is a single-value type which can be used. Example:
CREATE TABLE `buildings` (
`coordinate` POINT NOT NULL,
/* Even from v5.7.5 you can define an index for it */
SPATIAL INDEX `SPATIAL` (`coordinate`)
) ENGINE=InnoDB;
/* then for insertion you can */
INSERT INTO `buildings`
(...
T-SQL - function with default parameters
...- with parameters, with DEFAULT and via EXECUTE
SET NOCOUNT ON;
DECLARE
@Table SYSNAME = 'YourTable',
@Schema SYSNAME = 'dbo',
@Rows INT;
SELECT dbo.TableRowCount( @Table, @Schema )
SELECT dbo.TableRowCount( @Table, DEFAULT )
EXECUTE @Rows = dbo.TableRowCount @Table
SELECT @Rows
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PostgreSQL: How to change PostgreSQL user password?
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The user is an object, not a string. Compare with ALTER TABLE "table_name" or even SELECT * FROM "table_name". You couldn't use single quotes in these contexts with tables, and it's the same with users/roles.
– P Daddy
Apr 13 '16 at 5:11
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Sorting rows in a data table
We have two columns in a DataTable , like so:
12 Answers
12
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How to push both value and key into PHP array
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I would like to add my answer to the table and here it is :
//connect to db ...etc
$result_product = /*your mysql query here*/
$array_product = array();
$i = 0;
foreach ($result_product as $row_product)
{
$array_product [$i]["id"]= $row_product->id;
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Calculating moving average
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In data.table 1.12.0 new frollmean function has been added to compute fast and exact rolling mean carefully handling NA, NaN and +Inf, -Inf values.
As there is no reproducible example in the question there is not much more to addres...
What does “exec sp_reset_connection” mean in Sql Server Profiler? [duplicate]
...llocated memory
owned by the connection
Clears any work or temporary
tables that are created by the
connection
Kills all global cursors owned by the
connection
Closes any open SQL-XML handles that are open
Deletes any open SQL-XML related work tables
Closes all system tables
Clo...
Get the week start date and week end date from week number
...ent: https://msdn.microsoft.com/en-us/library/ms181598.aspx
And here is a table that lays it out for you.
| DATEFIRST VALUE | Formula Value | 7 - DATEFIRSTVALUE - 1
Monday | 1 | 5 | 7 - 1- 1 = 5
Tuesday | 2 | 4 | ...