# Place restrictive filters as early in the query as possible
Restrictive filters

 In all scenarios, early placement of filters in the query helps in reducing the intermediate solutions a query plan must consider. This means less memory and fewer compute resources are needed to execute the query. 

 The following example helps you understand these impacts. Suppose you write a query to return all of the people who live in `India`. One version of the query could be: 

```
MATCH (n)-[:lives_in]->(city)-[:part_of]->(country)
WITH country, collect(n.firstName + " "  + n.lastName) AS result
WHERE country.name = 'India'
RETURN result
```

 The above version of the query is not the most optimal way to achieve this use case. The filter `country.name = 'India'` appears later in the query pattern. It will first collect all persons and where they live, and group them by country, then filter for only the group for `country.name = India`. The optimal way to query for only people living in `India` and then perform the collect aggregation. 

```
MATCH (n)-[:lives_in]->(city)-[:part_of]->(country)
WHERE country.name = 'India'
RETURN collect(n.firstName + " "  + n.lastName) AS result
```

 A general rule is to place a filter as soon as possible after the variable is introduced.