SQL -Structured Query Language - Overview - SQL Syntax Tutorial

SQL queries are written using a unique set of rules and regulations called syntax. Some of the basic rules are –

• SQL is not case sensitive. But it better to write it in either lowercase or uppercase.
• SQL statement starts with any of the SQL command/keywords like SELECT, INSERT, UPDATE, DELETE, ALTER, DROP, CREATE, USE, SHOW, etc., and ends with a semicolon ‘; ‘.

Some of the syntax for better understanding

1. select * from regions;

   Run Query

2. SELECT * FROM REGIONS;

   Run Query

3. select * From REGIONS;

   Run Query

4. select * From REGIONS; select * From REGIONS;

   Run Query

5. select * From REGIONS select * From REGIONS;

   Run Query

The above example will clearly show how the query is not case sensitive.

1. In line 1, the whole statement is in lowercase. still, it gives the proper output.
2. In line 2, the whole statement is in uppercase. still, it gives the proper output.
3. In line 3, the statement is a mixture of uppercase and lowercase, still, it gives proper output
4. In line 4, An important part is there is two statement, which has been separated using a semicolon ‘; ‘.
5. In line 5, An important part is there is two statement, which has been separated without using a semicolon ‘; ‘. A single statement can be run without a semicolon. But if there are two statements without separating with the semicolon, then it will give an error.

Hence semicolon ‘; ‘ is very important in writing multiple SQL queries.

select * from regions

Run Query

The above query or statement is written singly. Hence it can run without the use of the semicolon.