diff --git a/docs/tutorials/query-language.md b/docs/tutorials/query-language.md index a7a093e8..35e9aeb6 100644 --- a/docs/tutorials/query-language.md +++ b/docs/tutorials/query-language.md @@ -23,7 +23,7 @@ let merlots = wines.filtered('variety == $0 && vintage <= $1', 'Merlot', maxYear ``` -### Relational operators +### Conditional operators You can use equality comparison on all property types: `==` and `!=` @@ -35,7 +35,7 @@ Example: let oldContacts = realm.objects('Contact').filtered('age > 2'); ``` -Note that for boolean properties, you should test against the expected keyword. +Note that for boolean properties, you should test against `true` or `false`. Example: ```JS @@ -43,7 +43,7 @@ let women = realm.objects('Contact').filtered('isMale == false'); ``` ### String operators -For string properties, prefix, suffix, and substring queries are supported by using the `BEGINSWITH`, `ENDSWITH`, and `CONTAINS` operators. +For string properties, prefix, suffix, and substring queries are supported by using the `BEGINSWITH`, `ENDSWITH`, `CONTAINS` and `LIKE` operators. For any string operation you can append `[c]` to the operator to make it case insensitive. @@ -53,6 +53,58 @@ let peopleWhoseNameContainsA = realm.objects('Contact').filtered('name CONTAINS[ let Johns = realm.objects('Contact').filtered('name ==[c] "john"'); ``` +You can do simple wildcard matching with `LIKE` which supports using `?` to match a single character and `*` to match zero or multiple characters. + +Example: +```JS +// Matches "John" and "Johnny" +let Johns = realm.objects('Contact').filtered('name LIKE "John*"'); +``` + ### Composition Use parentheses and the `&&`/`AND` and `||`/`OR` operators to compose queries. You can negate a predicate with `!`/`NOT`. +### Queries on collections + +When objects contain lists you can query into them using the collection operators `ANY`, `ALL` and `NONE`. + +Example: +```JS +// Find contacts with one or more teenage friends +let teens = realm.objects('Contact').filtered('ANY friends.age < 14'); + +// Find contacts where all friends are older than 21 +let adults = realm.objects('Contact').filtered('ALL friends.age > 21'); +``` + +You can query on aggregates over properties in the lists using the aggregate operators `.@count`, `.@avg`, `.@min`, `.@max` and `.@sum`. + +Example: +```JS +// Find contacts without friends +let teens = realm.objects('Contact').filtered('friends.@count == 0'); + +// Find contacts where the average age of their friends is above 40 +let adults = realm.objects('Contact').filtered('friends.@avg.age > 40"'); +``` + +Subqueries using the `SUBQUERY` operator allows you to filter the lists across multiple parameters while querying them. + +Example: +```JS +// Find contacts with friends above 21 in SF +let teens = realm.objects('Contact').filtered('SUBQUERY(friends, $friend, $friend.age > 21 AND $friend.city = 'SF').@count > 0'); +``` + +### Backlink queries + +Other objects can link to an object and you can query on that releationship using the `@links` and `@links.ClassName.PropertyName` syntax: + +Example: +```JS +// Find contacts with no incomming links +let lonely = realm.objects('Contact').filtered('@links.@count == 0); + +// Find contacts where someone from SF has them as friends +realm.objects('Contact').filtered('@links.Contact.friends.city == "SF"); +```