AVG using specific condition for each row
133742
CASE WHEN with GROUP BY
124972
How to count specific items in column?
33343
How to round an average to 2 decimal places in PostgreSQL?
53618
How to find average and median age from an aggregated frequency table
151672
Summing values if same second column value
106247
Count number of rows with conditions met in two columns
75495
Increased amount of each row in sql
55747
Grouping functions (tapply, by, aggregate) and the *apply family
140337
Using an aggregate function in where
54521
Making all row sums and column sums non-negative by a sequence of moves
63123
Excel: identifying if all values in a row are not equal
19627
Column count doesn't match value count at row 1
42491
How do I efficiently get "the most recent corresponding row"?
31119
Count number of rows per group and add result to original data frame
136871
R use ddply or aggregate
26190
Calculate values from specific fields for each row in a featureclass
2241
Get top 1 row of each group