Merge pull request enochtangg#3 from will7200/patch-1

Update README.md

Author: enochtangg

README.md

@@ -73,6 +73,11 @@ A quick reminder of all relevant SQL queries and examples on how to use them.
 * `SELECT` columns_names `FROM` table1 `UNION SELECT` column_name `FROM` table2;
 * `UNION` operator only selects distinct values, `UNION ALL` will allow duplicates
 
+### **ANY|ALL**: operator used to check subquery conditions used within a WHERE or HAVING clauses
+* The `ANY` operator returns true if any subquery values meet the condition
+* The `ALL` operator returns true if all subquery values meet the condition
+* `SELECT` columns_names `FROM` table1 `WHERE` column_name operator (`ANY`|`ALL`) (`SELECT` column_name `FROM` table_name `WHERE` condition);
+
 ### **GROUP BY**: statement often used with aggregate functions (COUNT, MAX, MIN, SUM, AVG) to group the result-set by one or more columns
 * `SELECT` column_name1, COUNT(column_name2) `FROM` table_name `WHERE` condition `GROUP BY` column_name1 `ORDER BY` COUNT(column_name2) DESC;