A comment is a readable explanation provided about something. The comments in the code are provided to explain the purpose of the code staement used. This enables the outside person to understand the need and use of that particular code.The comments are ignored by the compilers and are not executed. These are just for the explanatory purpose and are of great importance.We can add comments to columns in a sql table. These comments will explain the function or tell something about the column. If some other person is viewing and working on that table, he can get idea about the ... Read More

IF statement is a conditional statement in python. It checks for a particular condition and performs some action accordingly.Here, we will discuss the use of IF statement using python to interact with the sql database.SyntaxIF(condition, value_if_true, value_if_false)The IF statemen tcan be used with the SELECT clause to perform selection based on some criteria .Steps to use IF statement to select data from a table using MySQL in pythonimport MySQL connectorestablish connection with the connector using connect()create the cursor object using cursor() methodcreate a query using the appropriate mysql statementsexecute the SQL query using execute() methodclose the connectionSuppose we the following ... Read More

The data is inserted into the table in Mysql using the INSERT statement. While inserting the data into the table, either the data must be provided in the same order as the column definition in the database or the column names must be provided along with the data while using INSERT statement.To get and print the ID of the last inserted row, lastrowid is used. This is a special keyword which is used to get the ID of the last inserted row. There are certain prerequisites to be taken care of before using this method.The ID column must be the ... Read More

These are the functions used to perform the arithmetic operations on the column values in a table.The COUNT() function is used to return the number of rows which satisfy a certain condition.The SUM() function is used to return the sum of numerical values in a column in the table.The NULL values are ignored.SyntaxCOUNT()SELECT COUNT(column_name) FROM table_name WHERE conditionSUM()SELECT SUM(column_name) FROM table_nameSteps invloved to use count() and sum() functions on a table using MySQL in pythonimport MySQL connectorestablish connection with the connector using connect()create the cursor object using cursor() methodcreate a query using the appropriate mysql statementsexecute the SQL query using ... Read More

We can create copy of an existing table in mysql using Python. The entire table will be copied including the columns, the column definitions and all the rows of the table.SyntaxCREATE TABLE table_name SELECT * FROM existing_tabletable_name is the name of the new table to be created. existing_table is the name of the table which is to be copied.Steps to copy a table using MySQL in pythonimport MySQL connectorestablish connection with the connector using connect()create the cursor object using cursor() methodcreate a query using the appropriate mysql statementsexecute the SQL query using execute() methodclose the connectionSuppose, we have a table ... Read More

The rollback() method is one among the various methods in Python which is used to make the database transactions.Here, we will discuss about the rollback() method.The rollback() method is used to revert the last change or commit made to the database. If a condition arises such that the user is not satisfied with the changes made to the database, or if the transaction fails, then the rollback() method is operated to bring the database to its original state which was before committing the changes. This is a very important method as it helps in maintaing the integrity of the database ... Read More

The commit() method is one among the various methods in Python which is used to make the database transactions.Here, we will discuss about the commit() method. The commit() method is used to confirm the changes made by the user to the database. Whenever any change is made to the database using update or any other statements, it is necessary to commit the changes. If we donot use the commit() method after making any changes to the database, the database will not not be updated and changes will not be reflected.Syntaxdb.commit()db refers to the database connection object.Given below is an example ... Read More

LIKE is a operator in MySQL. The LIKE operator is used with the WHERE statement to search for a specific pattern in the table.Suppose you want to search for values which start with “a” in the table, the LIKE statement is used in such scenarios.There are two wildcard characters used with the LIKE clause.% − This sign represents zero, one or multiple characters._ (underscore) − This represents one single character.ExampleLIKE ‘a%’ - Searches for all the values starting with a.LIKE ‘%a’  -Searches for all the values which end with a.LIKE ‘_a%’ - Searches for all the values where ‘a’ is ... Read More

The MIN() and MAX() functions are used to perform arithmetic operations on the columns of the table.As the name suggests, the MIN() function is used to select and return the samllest value from the selected column.The MAX() function, on the other hand, selects and returns the highest value from the selected column.SyntaxMIN()SELECT MIN(column_name) FROM table_nameMAX()SELECT MAX(column_name) FROM table_nameSteps invloved in finding minimum and maximum value from a column in table using MySQL in pythonimport MySQL connectorestablish connection with the connector using connect()create the cursor object using cursor() methodcreate a query using the appropriate mysql statementsexecute the SQL query using execute() ... Read More

We can join two tables in SQL based on a common column between them or based on some specified condition. There are different types of JOIN available to join two SQL tables.Here, we will discuss about the SELF join on two tables.As the name signifies, SELF join is the join with the table itself. This join is performed between two copies of the same table. The rows of the table are matched with the other rows of the same table based on some condition.SyntaxSELECT a.coulmn1 , b.column2 FROM table_name a, table_name b WHERE condition;a and b are the two aliases ... Read More