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How to set initial value and auto increment in MySQL?
...r) values("kowalski's nuclear reactor.");
Step 4, interpret the output:
select * from penguins
prints:
'1001', 'We need more power!'
'1002', 'Time to fire up'
'1003', 'kowalski\'s nuclear reactor'
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mysql - how many columns is too many?
...every column to be returned by every query is perfectly normal; that's why SELECT statement lets you explicitly name the columns you need.
As a general rule, your table structure should reflect your domain model; if you really do have 70 (100, what have you) attributes that belong to the same entit...
#1071 - Specified key was too long; max key length is 1000 bytes
... the best prefix length for a given column? Here's a method to find out:
SELECT
ROUND(SUM(LENGTH(`menu_link`)<10)*100/COUNT(`menu_link`),2) AS pct_length_10,
ROUND(SUM(LENGTH(`menu_link`)<20)*100/COUNT(`menu_link`),2) AS pct_length_20,
ROUND(SUM(LENGTH(`menu_link`)<50)*100/COUNT(`menu_...
MySQL IF NOT NULL, then display 1, else display 0
...
SELECT c.name, IF(a.addressid IS NULL,0,1) AS addressexists
FROM customers c
LEFT JOIN addresses a ON c.customerid = a.customerid
WHERE customerid = 123
...
MySQL Database won't start in XAMPP Manager-osx
...-0, I changed the port number from 3306 to 3307.
Click on Manage Servers
Select MySQL Database
Click on Configure on your right
Change your port number to 3307
Click OK
Close your Control Panel and relaunch it.
You are now good to go.
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must appear in the GROUP BY clause or be used in an aggregate function
...
Yes, this is a common aggregation problem. Before SQL3 (1999), the selected fields must appear in the GROUP BY clause[*].
To workaround this issue, you must calculate the aggregate in a sub-query and then join it with itself to get the additional columns you'd need to show:
SELECT m.cname...
How can I do an UPDATE statement with JOIN in SQL Server?
...oesn't support MERGE):
ANSI/ISO:
update ud
set assid = (
select sale.assid
from sale
where sale.udid = ud.id
)
where exists (
select *
from sale
where sale.udid = ud.id
);
MySQL:
update ud u
inner join sale s on
u.id = s.udid
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How do write IF ELSE statement in a MySQL query
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You probably want to use a CASE expression.
They look like this:
SELECT col1, col2, (case when (action = 2 and state = 0)
THEN
1
ELSE
0
END)
as state from tbl1;
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json_encode is returning NULL?
...tf8 encoding: try to put mysql_query('SET CHARACTER SET utf8') before your SELECT query.
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rails + MySQL on OSX: Library not loaded: libmysqlclient.18.dylib
..... faced this issue..... did Following steps 1. gem uninstall mysql2 > selected option 3 2. gem install mysql2 3. added this to gemfile of project ---> gem 'mysql2', '~> 0.3.21' 4. bundle install
– Udit Kapahi
Jun 23 '16 at 9:53
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