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What's the difference between comma separated joins and join on syntax in MySQL? [duplicate]
For example if I were to have a table "Person" with a column "id" that references a column "id" in table "Worker"
5 Answers...
How to write lists inside a markdown table?
Can one create a list (bullets, numbered or not) inside a markdown table.
6 Answers
6
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MySQL table is marked as crashed and last (automatic?) repair failed
I was repairing this table suddenly server hanged and when I returned back all tables are ok but this one showing 'in use' and when I try to repair it doesn't proceed.
...
conditional unique constraint
...unt > 0.
http://msdn.microsoft.com/en-us/library/ms188258.aspx
CREATE TABLE CheckConstraint
(
Id TINYINT,
Name VARCHAR(50),
RecordStatus TINYINT
)
GO
CREATE FUNCTION CheckActiveCount(
@Id INT
) RETURNS INT AS BEGIN
DECLARE @ret INT;
SELECT @ret = COUNT(*) FROM CheckConstraint WHER...
JOIN queries vs multiple queries
...
if you are joining 3 or more tables on different keys, often databases (i.e. mysql) can only use one index per table, meaning maybe one of the joins will be fast (and use an index) whereas the others will be extremely slow. For multiple queries, you can ...
List all the files that ever existed in a Git repository
...$ git ff create
A database/migrations/2014_10_12_000000_create_users_table.php
A database/migrations/2014_10_12_100000_create_password_resets_table.php
A database/migrations/2015_05_11_200932_create_boletin_table.php
A database/migrations/2015_05_15_133500_create_usuarios_tab...
How to use index in select statement?
Lets say in the employee table, I have created an index(idx_name) on the emp_name column of the table.
8 Answers
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Foreign Key to non-primary key
I have a table which holds data, and one of those rows needs to exist in another table. So, I want a foreign key to maintain referential integrity.
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Splitting string into multiple rows in Oracle
...str(t.error, '[^,]+', 1, levels.column_value)) as error
from
temp t,
table(cast(multiset(select level from dual connect by level <= length (regexp_replace(t.error, '[^,]+')) + 1) as sys.OdciNumberList)) levels
order by name
EDIT:
Here is a simple (as in, "not in depth") explanation of t...
What is the dual table in Oracle?
I've heard people referring to this table and was not sure what it was about.
14 Answers
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