GROUP BY: This segregates records based on some given conditions. (It will find the position of ‘pen’ in the word ‘independence’)ġ5. INSTR: This returns a position of a string in another string. (It will fetch characters from the 1st to 5th position of a string)ġ4. SELECT SUBSTRING(customer_name,1,5) FROM customer_table SUBSTRING: Used to pick a specific character from a string by specifying the position.
‘%A_’ – The 2nd from the last letter will be A.ġ3. ‘%A%’ – A will be in between the string. LIKE: This operator uses the WHERE clause to search for a specified pattern in a string column. IN: This operator allows us to specify multiple values in a WHERE clause. WHERE emp_id BETWEEN 1 AND 10 SELECT * FROM employeeġ1. Mostly we use this where we want to specify a range of dates. BETWEEN: This operator selects records within a given range. If we specify NOT before any conditions, records that are not meeting those conditions will be fetched. WHERE department = 'IT' OR city = 'Bangalore' ĩ. OR: If two conditions are given, and one is met for a record, then that record will be fetched. WHERE name = 'stella' AND city = 'Bangalore' Ĩ. AND: If two conditions are given, and both are met for a record, then only the query will fetch that record. (**ORDER BY used here for sorting value in descending order)ħ. If we wish to the top 5 students of a class, then after sorting the results, we can use this LIMIT by specifying five so that it will only fetch the top 5 records. LIMIT: This is used to specify the number of records we want after executing the query. If we want to descend, we need to specify it after using the ORDER BY clause. But by default, it sorts in an ascending way. ORDER BY: Used to sort numeric and string values in ascending or descending manner. COUNT: Used to get the number of records present in a table.ĥ. SELECT DISTINCT col_name FROM table ģ. WHERE: Used forgiving conditions in the retrieval of records. DISTINCT: Used to fetch all the unique values from a table. SELECT: Used to fetch all the records from a table. If we want it in descending, then we need to specify it after using the ORDER BY clause)ġ. But by default, it sorts in an ascending manner. (Used to sort numeric and string values in ascending or descending manner. (BETWEEN clause will return records which satisfy the given range of conditions passed in the query) 
(WHERE command will fetch those records only, where the city will be ‘Delhi’)Ĭommand: SELECT cust_id, first_name, last_name,city, amount FROM customer (This will fetch specified columns from a table that are passed through a query)Ĭommand: SELECT cust_id, first_name, last_name, email,city FROM customer (This will fetch all the records with all attributes from a table)Ĭommand: SELECT cust_id, first_name, last_name, email,city
We will see some basic SELECT queries using some clauses to understand how this command works. Let’s consider there is a customer table with the following attributes. Here query will fetch all the records from table_name2 and will insert those into table_name1. INSERT INTO table_name1 SELECT * FROM table_name2
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