SQL filter: WHERE

Link: SQL

Filter strings §

• When filter by string names, use single quote
• double quote is reserved for referencing column names

  SELECT * FROM reviews
           WHERE manufacturer = 'Biogen'

Combine WHERE with AND, OR, NOT §

• When using multiple AND, OR, do not add comma between conditions!
• Use () bracket to prioritize and group the conditions

SELECT * FROM reviews
WHERE condition1
  AND/OR condition2
  AND/OR condition3;

Combine WHERE with NOT §

SELECT * FROM reviews
WHERE
  stars NOT BETWEEN 2 AND 4
  AND NOT stars = 5;

Combine WHERE with BETWEEN §

• WHERE...BETWEEN x AND y
• In SQL, BETWEEN is inclusive (close bracket)!

SELECT * FROM reviews
  WHERE year BETWEEN 2000 AND 2010;

Combine WHERE with IN §

WHERE ... IN ()

SELECT drug, manufacturer, units_sold
FROM pharmacy_sales
WHERE manufacturer IN ('Biogen', 'Bayer', 'Eli Lilly');

Combine WHERE with LIKE §

• WHERE ... LIKE '...'
• WHERE ... NOT LIKE '...'
• Often use with wildcard % 0 or multiple chars) and _ (single character)

SELECT product_id,
       manufacturer,
       drug
FROM pharmacy_sales
WHERE drug LIKE '%Relief%';