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Warning as error - How to rid these
...h of your projects and change that setting:
Right-click on your project, select "Properties".
Click "Build".
Switch "Treat warnings as errors" from "All" to "Specific warnings" or "None".
The location of this switch varies, depending on the type of project (class library vs. web application, for...
Fastest way to count exact number of rows in a very large table?
I have come across articles that state that SELECT COUNT(*) FROM TABLE_NAME will be slow when the table has lots of rows and lots of columns.
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How to reset sequence in postgres and fill id column with new data?
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SELECT setval('seq', 1, FALSE) should do the same (here, the third argument, FALSE, does the magic, as it shows that nextval must be 1 instead of 2)
– Vasilen Donchev
Sep 22 '15 at 14:43...
How to get the mysql table columns data type?
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You can use the information_schema columns table:
SELECT DATA_TYPE FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_name = 'tbl_name' AND COLUMN_NAME = 'col_name';
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List all tables in postgresql information_schema
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You should be able to just run select * from information_schema.tables to get a listing of every table being managed by Postgres for a particular database.
You can also add a where table_schema = 'information_schema' to see just the tables in the informat...
MySQL Select Query - Get only first 10 characters of a value
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Using the below line
SELECT LEFT(subject , 10) FROM tbl
MySQL Doc.
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How to select the nth row in a SQL database table?
I'm interested in learning some (ideally) database agnostic ways of selecting the n th row from a database table. It would also be interesting to see how this can be achieved using the native functionality of the following databases:
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SQL Server: Difference between PARTITION BY and GROUP BY
...y're used in different places. group by modifies the entire query, like:
select customerId, count(*) as orderCount
from Orders
group by customerId
But partition by just works on a window function, like row_number:
select row_number() over (partition by customerId order by orderId)
as OrderN...
How do I get textual contents from BLOB in Oracle SQL
...S of the text stored in the BLOB, CS of the database used for VARCHAR2) :
select utl_raw.cast_to_varchar2(dbms_lob.substr(BLOB_FIELD)) from TABLE_WITH_BLOB where ID = '<row id>';
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Postgres DB Size Command
..."pg_datbase" system table. Just apply the function to the names, as below.
select t1.datname AS db_name,
pg_size_pretty(pg_database_size(t1.datname)) as db_size
from pg_database t1
order by pg_database_size(t1.datname) desc;
If you intend the output to be consumed by a machine instead of a...