دستورات sql , کوئری ها در mysql در php

[saalek110]

ALTER TABLE Persons
ADD UNIQUE (ID);

افزودن یک ستون یونیکیو.

MySQL UNIQUE Constraint

The UNIQUE constraint ensures that all values in a column are unique.

www.w3schools.com

 

[saalek110]

CREATE TABLE Persons (
    ID int NOT NULL,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int,
    PRIMARY KEY (ID)
);

ایجاد یک جدول با یک ستون پرایمری key.

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ALTER TABLE Persons
ADD PRIMARY KEY (ID);

کوئری بالا افزودن یک ستون primaty key به جدول.

 

[saalek110]

CREATE TABLE Persons (
    ID int NOT NULL,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int,
    CHECK (Age>=18)
);

چک.
چک می کند که سن بالای ۱۸ باشد.

ALTER TABLE Persons
ADD CHECK (Age>=18);

کوئری بالا ، ایجاد ستون با چک.

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[saalek110]

CREATE TABLE Persons (
    ID int NOT NULL,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int,
    City varchar(255) DEFAULT 'Sandnes'
);

مقدار دیفالت داشتن یک ستون.یعنی اگر مقدار نداشت ، اون مقدار قرار داده بشه.

ALTER TABLE Persons
ALTER City SET DEFAULT 'Sandnes';

تغییر ستون و تنظیم دیفالت.

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[saalek110]

Indexes are used to retrieve data from the database more quickly than otherwise. The users cannot see the indexes, they are just used to speed up searches/queries.

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سالک: یک سری تعاریف بعدا تکمیل میشه...فعلا کوئری ها را اجازه دهید نقل کنم.

CREATE INDEX index_name
ON table_name (column1, column2, ...);

 

[saalek110]

ستون خود افزایش یابنده:

CREATE TABLE Persons (
    Personid int NOT NULL AUTO_INCREMENT,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int,
    PRIMARY KEY (Personid)
);

ALTER TABLE Persons AUTO_INCREMENT=100;

کوئری بالا عدد شروع را هم تعیین کرده ، یعنی از ۱۰۰ شروع به شمارش می کند.

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INSERT INTO Persons (FirstName,LastName)
VALUES ('Lars','Monsen');

در اینسرت بالا ، نیازی به افزودن Personid نیست. خوش افزوده می شود.

 

[saalek110]

MySQL Data Types​

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[saalek110]

MySQL Tryit Editor v1.0

یک جدول اینجا هست و شما می توانید کوئری تمرین کنید.

مثلا انتهای خط where بزارید... و یک شرطی بنویسید.

 

[saalek110]

SELECT * FROM Customers
WHERE Country = 'Mexico';

وقتی کشور ، مکزیکو باشد.

SELECT * FROM Customers
WHERE CustomerID = 1;

وقتی شماره مشتری ، ۱ باشد.

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[saalek110]

SELECT column1, column2, ...
FROM table_name
WHERE condition1 AND condition2 AND condition3 ...;

SELECT column1, column2, ...
FROM table_name
WHERE condition1 OR condition2 OR condition3 ...;

SELECT column1, column2, ...
FROM table_name
WHERE NOT condition;

SELECT * FROM Customers
WHERE Country = 'Germany' AND City = 'Berlin';

وقتی کشور آلمان باشد و شهر برلین باشد.

SELECT * FROM Customers
WHERE City = 'Berlin' OR City = 'Stuttgart';

وقتی شهر برلین یا اشتوتگارت باشد.

SELECT * FROM Customers
WHERE NOT Country = 'Germany';

وقتی کشور آلمان نباشد.

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[saalek110]

SELECT * FROM Customers
WHERE Country = 'Germany' AND (City = 'Berlin' OR City = 'Stuttgart');

SELECT * FROM Customers
WHERE NOT Country = 'Germany' AND NOT Country = 'USA';

 

[saalek110]

Like:

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[saalek110]

Free MySQL Book

Getting started with MySQL, Data Types, SELECT, Backticks, NULL, Limit and Offset, Creating databases, Using Variables, Comment MySQL, INSERT, DELETE, UPDATE, ORDER BY, Group By, Error 1055: ONLY_FULL_GROUP_BY: something is not in GROUP BY clause ..., Joins, UNION and Arithmetic

books.goalkicker.com

Book free

200 صفحه.

 

[saalek110]

mysql eBook

A mysql eBooks created from contributions of Stack Overflow users.

riptutorial.com

۲۷۰ صفحه.

 

[saalek110]

از اینستاگرام...

 

[saalek110]

دستور count :

SELECT COUNT(ProductID) AS NumberOfProducts FROM Products;

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W3Schools offers free online tutorials, references and exercises in all the major languages of the web. Covering popular subjects like HTML, CSS, JavaScript, Python, SQL, Java, and many, many more.

www.w3schools.com

MySQL Tryit Editor v1.0

www.w3schools.com

 

[saalek110]

SELECT count(*)
FROM information_schema.columns
WHERE table_name = 'tbl_ifo'

How do I count columns in a table

For example : id | name | age | gender ---------------------------- 1 | John | 15 | Male 2 | Maria | 18 | Female 3 | Steph | 19 | Female 4 | Jay | 21 | Male How can I count the co...

stackoverflow.com