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Predicates

Field Predicates#

  • Bool:
    • =, !=
  • Numeric:
    • =, !=, >, <, >=, <=,
    • IN, NOT IN
  • Time:
    • =, !=, >, <, >=, <=
    • IN, NOT IN
  • String:
    • =, !=, >, <, >=, <=
    • IN, NOT IN
    • Contains, HasPrefix, HasSuffix
    • ContainsFold, EqualFold (SQL specific)
  • JSON
    • =, !=
    • =, !=, >, <, >=, <= on nested values (JSON path).
    • Contains on nested values (JSON path).
    • HasKey, Len<P>
  • Optional fields:
    • IsNil, NotNil

Edge Predicates#

  • HasEdge. For example, for edge named owner of type Pet, use:

    client.Pet.
    Query().
    Where(pet.HasOwner()).
    All(ctx)
  • HasEdgeWith. Add list of predicates for edge predicate.

    client.Pet.
    Query().
    Where(pet.HasOwnerWith(user.Name("a8m"))).
    All(ctx)

Negation (NOT)#

client.Pet.
Query().
Where(pet.Not(pet.NameHasPrefix("Ari"))).
All(ctx)

Disjunction (OR)#

client.Pet.
Query().
Where(
pet.Or(
pet.HasOwner(),
pet.Not(pet.HasFriends()),
)
).
All(ctx)

Conjunction (AND)#

client.Pet.
Query().
Where(
pet.And(
pet.HasOwner(),
pet.Not(pet.HasFriends()),
)
).
All(ctx)

Custom Predicates#

Custom predicates can be useful if you want to write your own dialect-specific logic or to control the executed queries.

Get all pets of users 1, 2 and 3#

pets := client.Pet.
Query().
Where(func(s *sql.Selector) {
s.Where(sql.InInts(pet.FieldOwnerID, 1, 2, 3))
}).
AllX(ctx)

The above code will produce the following SQL query:

SELECT DISTINCT `pets`.`id`, `pets`.`owner_id` FROM `pets` WHERE `owner_id` IN (1, 2, 3)

Count the number of users whose JSON field named URL contains the Scheme key#

count := client.User.
Query().
Where(func(s *sql.Selector) {
s.Where(sqljson.HasKey(user.FieldURL, sqljson.Path("Scheme")))
}).
CountX(ctx)

The above code will produce the following SQL query:

-- PostgreSQL
SELECT COUNT(DISTINCT "users"."id") FROM "users" WHERE "url"->'Scheme' IS NOT NULL
-- SQLite and MySQL
SELECT COUNT(DISTINCT `users`.`id`) FROM `users` WHERE JSON_EXTRACT(`url`, "$.Scheme") IS NOT NULL

Get all users with a "Tesla" car#

Consider an ent query such as:

users := client.User.Query().
Where(user.HasCarWith(car.Model("Tesla"))).
AllX(ctx)

This query can be rephrased in 3 different forms: IN, EXISTS and JOIN.

// `IN` version.
users := client.User.Query().
Where(func(s *sql.Selector) {
t := sql.Table(car.Table)
s.Where(
sql.In(
s.C(user.FieldID),
sql.Select(t.C(user.FieldID)).From(t).Where(sql.EQ(t.C(car.FieldModel), "Tesla")),
),
)
}).
AllX(ctx)
// `JOIN` version.
users := client.User.Query().
Where(func(s *sql.Selector) {
t := sql.Table(car.Table)
s.Join(t).On(s.C(user.FieldID), t.C(car.FieldOwnerID))
s.Where(sql.EQ(t.C(car.FieldModel), "Tesla"))
}).
AllX(ctx)
// `EXISTS` version.
users := client.User.Query().
Where(func(s *sql.Selector) {
t := sql.Table(car.Table)
p := sql.And(
sql.EQ(t.C(car.FieldModel), "Tesla"),
sql.ColumnsEQ(s.C(user.FieldID), t.C(car.FieldOwnerID)),
)
s.Where(sql.Exists(sql.Select().From(t).Where(p)))
}).
AllX(ctx)

The above code will produce the following SQL query:

-- `IN` version.
SELECT DISTINCT `users`.`id`, `users`.`age`, `users`.`name` FROM `users` WHERE `users`.`id` IN (SELECT `cars`.`id` FROM `cars` WHERE `cars`.`model` = 'Tesla')
-- `JOIN` version.
SELECT DISTINCT `users`.`id`, `users`.`age`, `users`.`name` FROM `users` JOIN `cars` ON `users`.`id` = `cars`.`owner_id` WHERE `cars`.`model` = 'Tesla'
-- `EXISTS` version.
SELECT DISTINCT `users`.`id`, `users`.`age`, `users`.`name` FROM `users` WHERE EXISTS (SELECT * FROM `cars` WHERE `cars`.`model` = 'Tesla' AND `users`.`id` = `cars`.`owner_id`)

Get all pets where pet name contains a specific pattern#

The generated code provides the HasPrefix, HasSuffix, Contains, and ContainsFold predicates for pattern matching. However, in order to use the LIKE operator with a custom pattern, use the following example.

pets := client.Pet.Query().
Where(func(s *sql.Selector){
s.Where(sql.Like(pet.Name,"_B%"))
}).
AllX(ctx)

The above code will produce the following SQL query:

SELECT DISTINCT `pets`.`id`, `pets`.`owner_id`, `pets`.`name`, `pets`.`age`, `pets`.`species` FROM `pets` WHERE `name` LIKE '_B%'