Structured query language or SQL is a database programming language for operating the relational databases. Some major ways through which SQL is used is in conjunction with the relational databases for storing of data, retrieving data, and manipulating the stored data for various purposes in a relational database.
SQL programming aims at operating relational databases and to retrieve data and information from it. Some major operations of SQL include but not limited to database creation, fetching data, modifying the existing data, and deleting the rows and columns in the relational database storage. Structured query language follows ANSI standard, and there are also various versions of SQL are in use.
The top features for SQL as relational databases are:
- Very simple, easy to learn, and easy to use.
- It s a very versatile language which can work with various DBMS like Oracle, Microsoft, IBM, etc.
- SQL is ISO and ANSI certified for standard database creation and data management.
- SQL features a well-defined structure with established standards over a couple of decades.
- SQL is so quick in retrieving a huge amount of data.
- SQL helps everyone to manage databases even without knowing to code.
SQL programming is used widely for the below reasons:
- SQL will let you access data within relational databases
- SQL can be used to describe the data within a database.
- You can easily manipulate the data in relational databases using SQL queries.
- It is possible to embed SQL within other languages using various SQL modules and libraries.
- Using SQL, you can easily create or drop databases and database tables.
- SQL will let you create the views and stored procedures in databases.SQL can also be used for permissions for procedures, views, tables, etc.
SQL can also be used as a DDL (Data Definition Language) which you can use to define the particular database structure. It also acts as a Data Manipulation Language or DML, which can be used to maintain the existing databases. SQL is so powerful to be used for entering data, modifying, and extracting data. SQL can also be deployed as DCL or Data Control Language, which means you can also protect the database against any misuse or corruption. SQL is used extensively as a client or server-side language also to connect your front-end applications with the back-end to support the client or architectures. With these, SQL becomes a three-tier architecture for database, application server, and client.
Various SQL operations
Next, we will discuss some of the top SQL operations as pointed out by RemoteDBA.comexperts.
SQL SELECT Statement
SQL SELECT Statement is one of the most frequently used SQL statements. This command can be used to fetch data accordingly to the specific rules set or to display the full table. The needed data could be displayed after the query execution gets stored in the resultant table.
SQL FORMAT () – Date format in SQL
FORMAT () function is used to format specific fields into a standard displayable format. The FORMAT function syntax is as below.
In this, the column_name points to the ground where the formatting is needed.
Other SQL commands as below:
ALTER TABLE – This is to add more columns into the database tables, the syntax of ALTER TABLE as below.
AND here is the operator which combines two different conditions in SQL query. In this case, both the conditions should be true to get the row added to the result.
AS – Keyword that comes in the SQL queries which let you rename a table or column.
AVG() – Aggregate function which can return an average of the values in any numeric columns.
BETWEEN – This operator can be used for filtering the results set in the given range. The values to be in the range include but not limited to text, number, dates, or so.
CASE – The statement is to create various outputs for SELECT. This is to handle the if-then logical properly in SQL.
COUNT() – This function is an argument by taking the name of a particular column and then count the total rows if the corresponding columns which aren’t null.
DELETE – a statement used to delete any specified rows from tables.
CREATE TABLE – command can help create new tables in SQL databases. It can allow the users to define the name of a table as well as that of all columns in the tables.
GROUP BY – This clause can be used only with the aggregate functions in SQL. This can be used ideally along with SELECT statement for arranging data which are identical into the same groups.
INNER JOIN – is used to combine the rows of various tables if the condition of joining becomes true.
HAVING – it was added later to SQL queries as keyword WHERE cannot be used ideally with the aggregate functions.
INSERT – Itis used for adding new rows in the tables.
IS NULL and IS NOT NULL – these are operators which can be used ideally with the clause of WHERE statement testing for the empty values.
LIKE is an operator to be used with clause WHERE which can search for any specific patterns in the columns.
LIMIT – This clause can be used to let the users specify optimum rows in the results of a query
MAX() – this function can take the specific names of columns as an argument to return the biggest value.
MIN() – Just opposite to MAX(), it can return the column names with smallest values in it.
Here ‘OR’ functions as the operator who can filter the results to include the rows in which either of the given is the true condition.
ORDER BY – This clause indicates the user’s need to sort results by particular columns by considering the alphabetical progression or numeric progression.
OUTER JOIN – It can help combine the rows of various tables even when the condition of JOIN is not met.
ROUND() – Function which takes the name of a particular column and some integer as the arguments. It can also round up values in particular columns to the decimal places which are mentioned by the integers.
SELECT DISTINCT – statement which specifies the fact that the upcoming statement will be a query which may return some distinct values from the given columns.
Some other major SQL statements also include SELECT SUM (), UPDATE, WHERE, etc., which will discuss in further details in other articles. For the beginners into SQL, it is important to understand various combinations of the above syntaxes and commands to enjoy a fruitful SQL database administration experience.