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Difference between Pig and Hive? Why have both? [closed]
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Hive was designed to appeal to a community comfortable with SQL. Its philosophy was that we don't need yet another scripting language. Hive supports map and reduce transform scripts in the language of the user's choice (which can be embedded within SQL clauses). It is widel...
What is the difference between related SQLite data-types like INT, INTEGER, SMALLINT and TINYINT?
When creating a table in SQLite3, I get confused when confronted with all the possible datatypes which imply similar contents, so could anyone tell me the difference between the following data-types?
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rake db:schema:load vs. migrations
...n (very similar to your schema.rb file) and updating the schema_migrations table to reflect this change. Be very careful when doing this! You can easily delete your production data if you aren't careful.
As a side note, I strongly believe that you should never put data creation in the migration fil...
Pandas every nth row
...2nd row it would be df.iloc[1::5, :].
– Little Bobby Tables
Nov 13 '16 at 17:18
17
You can omit t...
Entity Framework DateTime and UTC
...);
}
/// <inheritdoc />
public override DataTable GetSchemaTable()
{
return source.GetSchemaTable();
}
/// <inheritdoc />
public override Stream GetStream(int ordinal)
{
return source.GetStream(ordi...
SELECT * WHERE NOT EXISTS
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You didn't join the table in your query.
Your original query will always return nothing unless there are no records at all in eotm_dyn, in which case it will return everything.
Assuming these tables should be joined on employeeID, use the foll...
Determine the data types of a data frame's columns
...- lapply(frame, class)
res_frame <- data.frame(unlist(res))
barplot(table(res_frame), main="Data Types", col="steelblue", ylab="Number of Features")
}
to produce a plot of all data types in your data frame. For the iris dataset we get the following:
data_types(iris)
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What is PAGEIOLATCH_SH wait type in SQL Server?
...stem.
In practice, this almost always happens due to large scans over big tables. It almost never happens in queries that use indexes efficiently.
If your query is like this:
Select * from <table> where <col1> = <value> order by <PrimaryKey>
, check that you have a composit...
Using LIMIT within GROUP BY to get N results per group?
...LECT id, GROUP_CONCAT(year ORDER BY rate DESC) grouped_year
FROM yourtable
GROUP BY id
Result:
-----------------------------------------------------------
| ID | GROUPED_YEAR |
-----------------------------------------------------------
| p01 | 2006,200...
Postgres: “ERROR: cached plan must not change result type”
...ement for execution.
Meanwhile, another script was modifying the database table, changing the data type of one of the columns being returned in the above SELECT statement.
I resolved this by restarting the application after the database table was modified. This reset the database connection, allow...