Index and Key both are different in RDBMS. Take a look all these differences quickly
Top differences between stored procedures and functions you can read and refresh quickly. Good summary for SQL developers.
Do review your SQL query program before put it into application program with these ideas. Read more.
Multiple nested query and Correlated sub-query both are different. Try to understand these with examples…
SQL query use for both INSERT into values and SELECT to save time.
SQL round and truncate decimal functions used in banking project.