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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...
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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TaifunWiFi 拓展：WiFi Manager WiFi管理器扩展 · App Inventor 2 中文网
...回当前设备的Android API级别。
ConnectSSID 连接网络(SSID,密码)
连接到指定的SSID（服务集标识符）。适用于Android >= 10。
使用新的点对点API来引导配置辅助设备，该API从Android 10开始可用。此API需要WRITE_SETTINGS权限。
DisconnectSSID...
#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
...
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 to use Git properly with Xcode?
...add this line to a .gitattributes file:
*.pbxproj text -crlf -diff -merge=union
Then git will always take both sides of a merge for the .pbxproject files, having the same effect as the script I provided only without any extra work.
Lastly, here is my complete .gitignore file, showing what I do h...
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.
...
Nginx serves .php files as downloads, instead of executing them
...an't understand a .php file (or for that matter any extension apart from a select few like .html, .js etc. which are static files)
Thus in order to run other kinds of files we need something that sits between nginx and the application (here the php application). This is where common gateway interfac...
“where 1=1” statement [duplicate]
...hould ignore it
No magic, just practical
Example Code:
commandText = "select * from car_table where 1=1";
if (modelYear <> 0) commandText += " and year="+modelYear
if (manufacturer <> "") commandText += " and value="+QuotedStr(manufacturer)
if (color <> "") command...