3. What Can SQL do?
• SQL can execute queries against a database
• SQL can retrieve data from a database
• SQL can insert records in a database
• SQL can update records in a database
• SQL can delete records from a database
• SQL can create new databases
• SQL can create new tables in a database
• SQL can create stored procedures in a database
• SQL can create views in a database
• SQL can set permissions on tables, procedures, and views
http://www.w3schools.com/sql/sql_intro.asp
7. Aggregation
SELECT COUNT(*)
FROM Table
WHERE column = ‘criteria’;
SELECT SUM(column)
FROM Table;
SELECT MIN(column), MAX(column)
FROM Table
WHERE column1 = ‘value’ AND column2 <= 5.0;
8. Filtering
SELECT *
FROM Table
WHERE column = ‘criteria’;
SELECT *
FROM Table
WHERE (column1 = ‘criteria’) AND (column2 = ‘criteria’);
SELECT *
FROM Table
WHERE (column1 = ‘criteria’) OR (column2 = ‘criteria’) OR (column3
= ‘criteria’);
9. Sorting
SELECT *
FROM Table
ORDER BY column ASC;
SELECT *
FROM Table
ORDER BY column DESC;
SELECT *
FROM Species
ORDER BY genus ASC, species ASC;
10. Saving Queries for Future Use
CREATE VIEW viewname AS
SELECT something, something2
FROM Table
GROUP BY whatever;