| No. | Relevant Functions | Description |
|---|---|---|
| 176 | window: dense_rank() ifnull() |
Second Highest Salary |
| \177 | window: dense_rank() or ifnull()+limit() |
UDFUNCTION:Nth Highest Salary |
| 180 | NO LAG() LEAD()in mySQL | Consecutive Numbers |
| 181 | self join | Employees Earning More Than Their Managers |
| 182 | Group by + having | Duplicate Emails |
| 183 | left join | Customers Who Never Order |
| 184 | window: rank() |
Department Highest Salary |
| 185 | window: dense_rank() |
Department Top Three Salaries |
| 197 | self join | Rising Temperature |
| 262 | BETWEEN() |
Trips and Users |
| 511 | window: dense_rank() |
Game Play Analysis: find first_login date |
| 550 | AVG(),DATEDIFF(),MIN() |
Game Play Analysis IV |
| \608 | MOD(), CASE WHEN |
Exchange Seats |
| 626 | IS NULL, NOT IN |
GTree Node |
| \1077 | Union() or CTE: with recursive |
Project Employees III: find the most experiecned employees |
| \1158 | On vs Where |
Market Analysis I |
| 1270 | window: rank() |
All People Report to the Given Manager |
| 1285 | window: row_number() |
Find the Start and End Number of Continuous Ranges |
| 1308 | window: sum() |
Running Total for Different Genders |
| 1369 | window: count()+ rank() |
Get the Second Most Recent Activity |
| \1407 | IFNULL() |
Top Travellers: Repeat names(don't group by) |
| 1412 | rank()*2: decending / ascending |
Find the Quiet Students in All Exams |
| 1532 | window: rank() |
The Most Recent Three Orders |
| 1549 | max() |
The Most Recent Orders for Each Product: keep the duplicates |
| 1596 | window: rank() |
The Most Frequently Ordered Products for Each Customer |
| \1613 | CTE: with recursive |
Find the Missing IDs |
| 1709 | window: LEAD() |
Biggest Window Between Visits |
| \1767 | CTE: with recursive |
Find the Subtasks That Did Not Execute |
| 1949 | Union + Join |
Strong Friendship |
| 1951 | window: rank() |
All the Pairs With the Maximum Number of Common Followers |
| 1972 | window: dense_rank()+ Union |
First and Last Call On the Same Day |
- Trips and Users
sum()
avg()
mean()
max() / min()
count()
’*‘ multiply
/ divid
% remainder
abs() absolute
stddev() Standard deviation
cbrt() cubed root
date_sub('2022-8-20', INTERVAL 3 day), to create new date
date_add'2022-8-20', INTERVAL 3 day), to create new date
date_format(day,"%Y-%m-%d"), to extract only date from column 'day'
age(col1, col2), calculate the gap year between two columns, col1(later) > col2
datediff('2022-8-20','2022-8-19'), calculate the days diff between two columns, col1(later) > col2
coalesce() return the 1st not null value
round()
cast('2022-8-20' as DATE) transfrom datatype
group_concat(col [ORDER BY col SEPARATOR ',']) Concatenate a column according to specific conditions