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MySQL DISTINCT on a GROUP_CONCAT()
I am doing SELECT GROUP_CONCAT(categories SEPARATOR ' ') FROM table . Sample data below:
6 Answers
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How can I retrieve Id of inserted entity using Entity framework? [closed]
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Let's consider the following scenario:table1 is supposed to generate an @@identity to use it in table2. Both table1 and table2 are supposed to be in the same transaction for e.g. one SaveChange operation must save both table's data. @@identity won't be generated ...
PostgreSQL: Difference between text and varchar (character varying)
...ange the limit in live environment (requires exclusive lock while altering table)
varchar – just like text
text – for me a winner – over (n) data types because it lacks their problems, and over varchar – because it has distinct name
The article does detailed testing to show that the...
mongodb: insert if not exists
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You may use Upsert with $setOnInsert operator.
db.Table.update({noExist: true}, {"$setOnInsert": {xxxYourDocumentxxx}}, {upsert: true})
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Logical operators for boolean indexing in Pandas
...[4])
>>> a3[np.bitwise_and(a1, a2)]
array([1, 1, 1, 2])
Summary table
Logical operator | NumPy logical function | NumPy bitwise function | Bitwise operator
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and | np.logical_and | np...
Alternate output format for psql
I am using PostgreSQL 8.4 on Ubuntu. I have a table with columns c1 through cN . The columns are wide enough that selecting all columns causes a row of query results to wrap multiple times. Consequently, the output is hard to read.
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Is having an 'OR' in an INNER JOIN condition a bad idea?
... to improve the speed of an immensely slow query (several minutes on two tables with only ~50,000 rows each, on SQL Server 2008 if it matters), I narrowed down the problem to an OR in my inner join, as in:
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Sqlite: CURRENT_TIMESTAMP is in GMT, not the timezone of the machine
I have a sqlite (v3) table with this column definition:
11 Answers
11
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Creation timestamp and last update timestamp with Hibernate and MySQL
...ons, you can use @PrePersist and @PreUpdate event hooks do this:
@Entity
@Table(name = "entities")
public class Entity {
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private Date created;
private Date updated;
@PrePersist
protected void onCreate() {
created = new Date();
}
@PreUpdate
protected void onUpdate() {
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Mysql order by specific ID values
...and FIELD function.
See http://lists.mysql.com/mysql/209784
SELECT * FROM table ORDER BY FIELD(ID,1,5,4,3)
It uses Field() function, Which "Returns the index (position) of str in the str1, str2, str3, ... list. Returns 0 if str is not found" according to the documentation. So actually you sort th...