Topics:
- Conceitual Project: ER/ERE and UML
- Relational algebra
- SQL/NoSQL
Tips:
- In SQL, keywords are not case-sensitive, but it's a good practice to make keywords uppercase to distinguish them from other parts of your query, like colummns and table names.
- To select multiple columns from a table, separate the column names with commas.
- SELECT DISTINCT to remove duplicate tuples.
- Functions: COUNT()
- If you want to count the number of non-missing values in a particular column, you can use COUNT() on just that column.
- You can combine COUNT() with DISTINCT to count the number of distinct values in a column.