JSONPathBuilder
§Constructors
§Methods
Access an element of a JSON array in a specific location.
Since there's no guarantee an element exists in the given array location, the resulting type is always nullable. If you're sure the element exists, you should use SelectQueryBuilder.$assertType to narrow the type safely.
See also {@link key} to access properties of JSON objects.
Examples
db.selectFrom('person').select(eb =>
eb.ref('nicknames', '->').at(0).as('primary_nickname')
)
The generated SQL (PostgreSQL):
```sql
select "nicknames"->0 as "primary_nickname" from "person"
Combined with {@link key}:
db.selectFrom('person').select(eb =>
eb.ref('experience', '->').at(0).key('role').as('first_role')
)
The generated SQL (PostgreSQL):
select "experience"->0->'role' as "first_role" from "person"
You can use 'last'
to access the last element of the array in MySQL:
db.selectFrom('person').select(eb =>
eb.ref('nicknames', '->$').at('last').as('last_nickname')
)
The generated SQL (MySQL):
select `nicknames`->'$[last]' as `last_nickname` from `person`
Or '#-1'
in SQLite:
db.selectFrom('person').select(eb =>
eb.ref('nicknames', '->>$').at('#-1').as('last_nickname')
)
The generated SQL (SQLite):
select "nicknames"->>'$[#-1]' as `last_nickname` from `person`
Access a property of a JSON object.
If a field is optional, the resulting type will be nullable.
See also {@link at} to access elements of JSON arrays.
Examples
db.selectFrom('person').select(eb =>
eb.ref('address', '->').key('city').as('city')
)
The generated SQL (PostgreSQL):
select "address"->'city' as "city" from "person"
Going deeper:
db.selectFrom('person').select(eb =>
eb.ref('profile', '->$').key('website').key('url').as('website_url')
)
The generated SQL (MySQL):
select `profile`->'$.website.url' as `website_url` from `person`
Combined with {@link at}:
db.selectFrom('person').select(eb =>
eb.ref('profile', '->').key('addresses').at(0).key('city').as('city')
)
The generated SQL (PostgreSQL):
select "profile"->'addresses'->0->'city' as "city" from "person"