SQL: Using Predicates
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This document discusses various SQL predicates that can be used in the WHERE clause including comparisons for equality, inequality, less than, greater than, use of characters, between, null values, similar values using LIKE, IN lists, and subqueries. It provides examples of SQL statements using each of these predicates in the WHERE clause to filter query results.
SQL: Using Predicates
- 2. WHERE? (Comparisons) Equal To IN_STOCK = 47 Not Equal To IN_STOCK <> 47 Less Than IN_STOCK < 47 Greater Than IN_STOCK > 47
- 3. WHERE? (Characters) Using Characters: CD_TITLE = ‘The Wall’ ● Note the single tick marks around the text!
- 4. WHERE? (Between) WHERE RETAIL_PRICE >= 14 AND RETAIL_PRICE <= 20 Same as: WHERE RETAIL_PRICE BETWEEN 14 AND 20
- 5. WHERE? (Null) WHERE PHONE_NUM IS NULL WHERE PHONE_NUM IS NOT NULL
- 6. WHERE? (Similar Values) WHERE LAST_NAME LIKE ‘Smi%’ WHERE LAST_NAME LIKE ‘%th’ WHERE LAST_NAME LIKE ‘Smi__’ WHERE LAST_NAME LIKE ‘___th’
- 7. WHERE? (IN List) WHERE STATE IN (‘IL’,’MO’,’AK’) Same as: WHERE STATE = ‘IL’ OR STATE = ‘MO’ OR STATE = ‘AK’
- 8. Subqueries SELECT TITLE, ARTIST FROM COMPACT_DISC_ARTISTS WHERE TITLE IN (SELECT CD_NAME FROM COMPACT_DISC_INVENTORY WHERE IN_STOCK > 10);
- 9. Subqueries SELECT TITLE, ARTIST FROM COMPACT_DISC_ARTISTS WHERE TITLE NOT IN (SELECT CD_NAME FROM COMPACT_DISC_INVENTORY WHERE IN_STOCK > 10);
- 10. Subqueries (EXISTS) SELECT * FROM COMPACT_DISC_INVENTORY WHERE EXISTS (SELECT TITLE FROM COMPACT_DISC_ARTISTS WHERE ARTIST = ‘Billy Joel’ AND COMPACT_DISC_INVENTORY.CD_NAME = COMPACT_DISC_ARTISTS.TITLE);