ALTER TABLE Persons
ADD UNIQUE (ID);
CREATE TABLE Persons (
ID int NOT NULL,
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Age int,
PRIMARY KEY (ID)
);ALTER TABLE Persons
ADD PRIMARY KEY (ID);CREATE TABLE Persons (
ID int NOT NULL,
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Age int,
CHECK (Age>=18)
);ALTER TABLE Persons
ADD CHECK (Age>=18);CREATE TABLE Persons (
ID int NOT NULL,
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Age int,
City varchar(255) DEFAULT 'Sandnes'
);ALTER TABLE Persons
ALTER City SET DEFAULT 'Sandnes';CREATE INDEX index_name
ON table_name (column1, column2, ...);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;INSERT INTO Persons (FirstName,LastName)
VALUES ('Lars','Monsen');
SELECT * FROM Customers
WHERE Country = 'Mexico';SELECT * FROM Customers
WHERE CustomerID = 1;
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';SELECT * FROM Customers
WHERE City = 'Berlin' OR City = 'Stuttgart';SELECT * FROM Customers
WHERE NOT Country = 'Germany';
SELECT COUNT(ProductID) AS NumberOfProducts FROM Products;SELECT count(*)
FROM information_schema.columns
WHERE table_name = 'tbl_ifo'
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