Presentation given on SQL for a librarian audience

1. TechTalk
Linked DataWorking Group
19 July 2016
SQL
Allison Jai O’Dell | AJODELL@ufl.edu

2. SQL
Structured Query Language:
a standard language for accessing and manipulating relational databases

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

4. Basic Queries
SELECT column
FROM Table;
SELECT column1, column2, column3
FROM Table;
SELECT *
FROM Table;

5. DistinctValues
SELECT DISTINCT column
FROM Table;
SELECT DISTINCT column1, column2
FROM Table;

6. CalculatedValues
SELECT weight/1000.0
FROM Specimens;
SELECT name, AVG(records)
FROM employees
GROUP BY name;
Expressions can use any fields, any arithmetic operators (+, -, *, and /)
and a variety of built-in functions

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;

11. Joins
SELECT *
FROM Table1
JOIN Table2
ON Table1.column = Table2.column;
SELECT *
FROM Table1
JOIN Table2
USING (column);