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Understanding exactly when a data.table is a reference to (vs a copy of) another data.table
...g a little trouble understanding the pass-by-reference properties of data.table . Some operations seem to 'break' the reference, and I'd like to understand exactly what's happening.
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How to select rows that have current day's timestamp?
I am trying to select only today's records from a database table.
9 Answers
9
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Join between tables in two different databases?
...ccount has appropriate permissions you can use:
SELECT <...>
FROM A.table1 t1 JOIN B.table2 t2 ON t2.column2 = t1.column1;
You just need to prefix the table reference with the name of the database it resides in.
sha...
How to check existence of user-define table type in SQL Server 2008?
I have a user-defined table type. I want to check it's existence before editing in a patch using OBJECT_ID(name, type) function.
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When should I use cross apply over inner join?
...readable and probably less efficient.
Update:
Just checked.
master is a table of about 20,000,000 records with a PRIMARY KEY on id.
This query:
WITH q AS
(
SELECT *, ROW_NUMBER() OVER (ORDER BY id) AS rn
FROM master
),
t AS
(
SELEC...
How to truncate a foreign key constrained table?
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You cannot TRUNCATE a table that has FK constraints applied on it (TRUNCATE is not the same as DELETE).
To work around this, use either of these solutions. Both present risks of damaging the data integrity.
Option 1:
Remove constraints
Perform...
What is the maximum length of a table name in Oracle?
What are the maximum length of a table name and column name in Oracle?
12 Answers
12
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Auto increment in phpmyadmin
... column. I guess the phpMyAdmin version is 3.5.5 but not sure.
Click on Table > Structure tab > Under Action
Click Primary (set as primary),
click on Change on the pop-up window, scroll left and check A_I. Also make sure you have selected None for Default
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How big is too big for a PostgreSQL table?
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Rows per a table won't be an issue on it's own.
So roughly speaking 1 million rows a day for 90 days is 90 million rows. I see no reason Postgres can't deal with that, without knowing all the details of what you are doing.
Depending o...
postgresql - add boolean column to table set default
Is this proper postgresql syntax to add a column to a table with a default value of false
5 Answers
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