CREATE TABLE employee

​

   ( employee_id VARCHAR(20),

​

    Name VARCHAR (20),

​

    Address VARCHAR (20),

​

    Mobile_no  SMALLINT);

​

enable the extension, you will need to edit the php.ini file on your server and add the following line:

​

extension=mysqli.so

This warning message typically occurs when PHP is unable to locate or load the mysqli extension. There are a few potential solutions you can try to resolve this issue:

​

1. Verify mysqli Extension Installation: You can start by confirming that the mysqli extension is installed on your system. Run the following command on your terminal:

   ```

   php -m | grep mysqli

   ```

   If mysqli does not appear in the list, you will need to install or enable it. You can usually do this by installing the `php-mysqli` package using your system's package manager (e.g., `apt`, `yum`, or `brew`).

​

2. Check php.ini Configuration: Ensure that the mysqli extension is correctly configured in your `php.ini` file. Locate the line with `extension=mysqli`, and remove any commenting (`;`) before the line. Save the changes and restart your web server.

​

   For example, on Ubuntu the php.ini file is located in `/etc/php/{PHP_VERSION}/apache2/php.ini` for Apache and `/etc/php/{PHP_VERSION}/cli/php.ini` for CLI. Replace `{PHP_VERSION}` with the appropriate version number.

​

3. Verify Extension File Existence: Double-check if the mysqli.so library file exists on the specified paths mentioned in the error message. In your case, it should be located at either `/usr/lib/php/20190902/mysqli` or `/usr/lib/php/20190902/mysqli.so`. If the file is missing, you might need to reinstall or recompile PHP with mysqli support.

​

4. Mismatched PHP Versions: It's possible that there may be multiple PHP

Adds a constraint that limits the value which can be added to a column.

Example 1 (MySQL): Makes sure any users added to the users table are 18

or over.

CREATE TABLE users (

first_name varchar(255),

age int,

CHECK (age>=18)

);

Example 2 (MySQL): Adds a check after the table has already been

created.

ALTER TABLE users

ADD CHECK (age>=18);

select * from movie where mname like'%r' and where category='family';

CREATE TABLE orchestra(

ORCHESTRA_ID int(15),

ORCHESTRA_NAME varchar(30),

ORCHESTRA_LOC varchar(15),

ORCHESTRA_HOURS int(10)

);

​

CREATE TABLE Provider (ProviderID CHAR(6) not null, FirstName VARCHAR(24) not null,

                       LastName VARCHAR(64) not null, PRIMARY KEY (ProviderID) );

INSERT INTO Provider (ProviderID, LastName, FirstName) 

VALUES ('123456', 'Spock', 'Ben');

SELECT*FROM Provider;

ALTER TABLE Provider ADD COLUMN HireDate date;

UPDATE Provider SET FirstName = 'Ben' WHERE ProviderID = '123456';

INSERT INTO Provider (ProviderID, LastName, FirstName, HireDate)

VALUES ('123457', 'Schweitzer', 'Albert', '1990-05-09');

INSERT INTO Provider (ProviderID, LastName, FirstName, HireDate)

VALUES ('123458', 'Shepherd', 'Derek', '2005-03-27');

INSERT INTO Provider (ProviderID, LastName, FirstName, HireDate)

VALUES ('123459', 'Sloan', 'Mark', '2005-03-27');

INSERT INTO Provider (ProviderID, LastName, FirstName, HireDate)

VALUES ('123460', 'Thomas', 'Brett', '2020-01-15');

SELECT*FROM Provider;

SELECT LastName, HireDate FROM Provider;

SELECT DISTINCT HireDate FROM Provider;

SELECT LastName, FirstName FROM Provider WHERE ProviderID = '123456';

SELECT ProviderID, LastName FROM Provider WHERE Hiredate >= '2010-01-01';

SELECT*FROM Provider WHERE HireDate BETWEEN '1990-01-01'

AND '2020-03-31';

SELECT ProviderID, LastName, FirstName FROM Provider WHERE HireDate is NULL

ALTER TABLE Provider ADD COLUMN Salary float;

UPDATE Provider SET Salary = 65000 WHERE ProviderID = '123456';

CREATE TABLE Provider (ProviderID CHAR(6) not null, FirstName VARCHAR(24) not null,

                       LastName VARCHAR(64) not null, PRIMARY KEY (ProviderID) );

INSERT INTO Provider (ProviderID, LastName, FirstName) 

VALUES ('123456', 'Spock', 'Ben');

SELECT*FROM Provider;

ALTER TABLE Provider ADD COLUMN HireDate date;

UPDATE Provider SET FirstName = 'Ben' WHERE ProviderID = '123456';

INSERT INTO Provider (ProviderID, LastName, FirstName, HireDate)

VALUES ('123457', 'Schweitzer', 'Albert', '1990-05-09');

INSERT INTO Provider (ProviderID, LastName, FirstName, HireDate)

VALUES ('123458', 'Shepherd', 'Derek', '2005-03-27');

INSERT INTO Provider (ProviderID, LastName, FirstName, HireDate)

VALUES ('123459', 'Sloan', 'Mark', '2005-03-27');

INSERT INTO Provider (ProviderID, LastName, FirstName, HireDate)

VALUES ('123460', 'Thomas', 'Brett', '2020-01-15');

SELECT*FROM Provider;

SELECT LastName, HireDate FROM Provider;

SELECT DISTINCT HireDate FROM Provider;

SELECT LastName, FirstName FROM Provider WHERE ProviderID = '123456';

SELECT ProviderID, LastName FROM Provider WHERE Hiredate >= '2010-01-01';

SELECT*FROM Provider WHERE HireDate BETWEEN '1990-01-01'

AND '2020-03-31';

SELECT ProviderID, LastName, FirstName FROM Provider WHERE HireDate is NULL

ALTER TABLE Provider ADD COLUMN Salary float;

UPDATE Provider SET Salary = 65000 WHERE ProviderID = '123456';

CREATE TABLE Provider (ProviderID CHAR(6) not null, FirstName VARCHAR(24) not null,

                       LastName VARCHAR(64) not null, PRIMARY KEY (ProviderID) );

INSERT INTO Provider (ProviderID, LastName, FirstName) 

VALUES ('123456', 'Spock', 'Ben');

SELECT*FROM Provider;

ALTER TABLE Provider ADD COLUMN HireDate date;

UPDATE Provider SET FirstName = 'Ben' WHERE ProviderID = '123456';

INSERT INTO Provider (ProviderID, LastName, FirstName, HireDate)

VALUES ('123457', 'Schweitzer', 'Albert', '1990-05-09');

INSERT INTO Provider (ProviderID, LastName, FirstName, HireDate)

VALUES ('123458', 'Shepherd', 'Derek', '2005-03-27');

INSERT INTO Provider (ProviderID, LastName, FirstName, HireDate)

VALUES ('123459', 'Sloan', 'Mark', '2005-03-27');

INSERT INTO Provider (ProviderID, LastName, FirstName, HireDate)

VALUES ('123460', 'Thomas', 'Brett', '2020-01-15');

SELECT*FROM Provider;

SELECT LastName, HireDate FROM Provider;

SELECT DISTINCT HireDate FROM Provider;

SELECT LastName, FirstName FROM Provider WHERE ProviderID = '123456';

SELECT ProviderID, LastName FROM Provider WHERE Hiredate >= '2010-01-01';

SELECT*FROM Provider WHERE HireDate BETWEEN '1990-01-01'

AND '2020-03-31';

SELECT ProviderID, LastName, FirstName FROM Provider WHERE HireDate is NULL

ALTER TABLE Provider ADD COLUMN Salary float;

UPDATE Provider SET Salary = 65000 WHERE ProviderID = '123456';

UPDATE Provider SET Salary = 9500 WHERE ProviderID = '123457';

​

​

CREATE TABLE Provider (ProviderID CHAR(6) not null, FirstName VARCHAR(24) not null,

                       LastName VARCHAR(64) not null, PRIMARY KEY (ProviderID) );

INSERT INTO Provider (ProviderID, LastName, FirstName) 

VALUES ('123456', 'Spock', 'Ben');

SELECT*FROM Provider;

ALTER TABLE Provider ADD COLUMN HireDate date;

UPDATE Provider SET FirstName = 'Ben' WHERE ProviderID = '123456';

INSERT INTO Provider (ProviderID, LastName, FirstName, HireDate)

VALUES ('123457', 'Schweitzer', 'Albert', '1990-05-09');

INSERT INTO Provider (ProviderID, LastName, FirstName, HireDate)

VALUES ('123458', 'Shepherd', 'Derek', '2005-03-27');

INSERT INTO Provider (ProviderID, LastName, FirstName, HireDate)

VALUES ('123459', 'Sloan', 'Mark', '2005-03-27');

INSERT INTO Provider (ProviderID, LastName, FirstName, HireDate)

VALUES ('123460', 'Thomas', 'Brett', '2020-01-15');

SELECT*FROM Provider;

SELECT LastName, HireDate FROM Provider;

SELECT DISTINCT HireDate FROM Provider;

SELECT LastName, FirstName FROM Provider WHERE ProviderID = '123456';

SELECT ProviderID, LastName FROM Provider WHERE Hiredate >= '2010-01-01';

SELECT*FROM Provider WHERE HireDate BETWEEN '1990-01-01'

AND '2020-03-31';

SELECT ProviderID, LastName, FirstName FROM Provider WHERE HireDate is NULL

ALTER TABLE Provider ADD COLUMN Salary float;

UPDATE Provider SET Salary = 65000 WHERE ProviderID = '123456';

UPDATE Provider SET Salary = 9500 WHERE ProviderID = '123457';