| Term | Definition |
|---|
| <= | less than or equal to |
| >= | greater than or equal to |
| BETWEEN | used to define range limits |
| IN | used to check whether an attribute value matches a value contained within a (sub)set of listed values |
| <> | Not equal to |
| IS NULL | used to check whether an attribute value is null |
| EXISTS | used to check whether an attribute has a value. |
| LIKE | used to check for similar character strings |
| * | matches any number of characters. it can be used as the first or last character in the character string |
| ? | matches any single alphabetic character |
| AND | joins two or more conditions and returns results when all are true |
| OR | joins two or more conditions and returns results when any are true |
| NOT | negates an expression |
| # | qualifies dates |
| 'text' | qualifies text |
| ORDER BY | lists in sequence |
| SUM() | gives the total of all rows, satisfying any condition, of the given column |
| AVG() | gives the average of the given column |
| MAX() | gives the largest figure in the given column |
| MIN() | gives the smallest figure in the given column |
| COUNT() | gives the number of rows satisfying the condition |
| COUNT(*) | counts the number of rows |
| DAY() | returns today’s date |
| YEAR() | returns only the year from a date field |
| ROUND(attribute, 0) | rounds to the nearest whole number |
| GROUP BY | indicate columns to summarize on |
| HAVING | indicate group conditions |
| DISTINCT | omits records that contain duplicate data in the selected fields |
| table.attribute | format used to identify an attribute of a table when tables being joined have attributes of the same name |
| & ' ' & | to combine two attributes into a single column |
| nested query | query inside a query. use in WHERE and HAVING conditions |
Combine with other sets
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