Module 8
SQL
Common Questions
Does the order of SQL commands matter while querying tables? Do we have to start with the SELECT command?
No, the order of commands in SQL doesn’t matter. However, the most common way to write your SQL queries is in this order: SELECT, FROM, JOIN, WHERE, GROUP BY, GROUP BY, ORDER BY, and LIMIT. Regardless of what order the commands are written, SQL will be reading your commands in the following order: FROM, JOIN, WHERE, GROUP BY, HAVING, SELECT, ORDER, LIMIT.
Do we have to define primary keys?
SQL tables need primary keys to be joinable, and to be easily referenced afterwards. Hence, every SQL table needs to have a primary key defined.
Can we have two columns of the same name in a table?
Columns in the same table cannot have the same name.
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