Basics

Building SQL

+(unaryPlus)

Concatenate SQL strings using the + operator.

kueryClient
    .sql {
        +"SELECT * FROM users"
        +"WHERE user_id = 1"
    }

Of course, if there is no need to concatenate, you don't have to.

kueryClient
    .sql {
        +"""
        SELECT * FROM users
        WHERE user_id = 1
        """.trimIndent()
    }

fun add(sql: String)

It is an alias for +(unaryPlus). However, since the argument is annotated with org.intellij.lang.annotations.Language, if you are using a JetBrains IDE, you will get syntax assistance.

Binding Parameters

When you want to bind parameters, use string interpolation.

val userId = "..."
kueryClient
    .sql {
        +"""
        SELECT * FROM users
        WHERE user_id = $userId
        """
    }

Logic such as if and for ...etc

Just write using Kotlin syntax. There is no need to learn special syntax.

kueryClient
    .sql {
        +"SELECT * FROM users"
        +"WHERE"
        +"status = $status"
        if (vip != null) {
            +"AND vip = $vip"
        }
    }

Fetch Result

kuery-client-spring-data-r2dbc/jdbc both have a minimal interface. In the case of kuery-client-spring-data-r2dbc, it will be a suspend function.

(suspend) fun singleMap(): Map<String, Any?>

Receives the results as a map.

val map: Map<String, Any?> = kueyClient
    .sql { +"SELECT * FROM users WHERE user_id = 1" }
    .singleMap()

(suspend) fun singleMapOrNull(): Map<String, Any?>?

Receives the results as a map.

val map: Map<String, Any?>? = kueyClient
    .sql { +"SELECT * FROM users WHERE user_id = 1" }
    .singleMapOrNull()

(suspend) fun <T : Any> single(returnType: KClass<T>): T

Receives the results converted to the specified type.

val user: User = kueyClient
    .sql { +"SELECT * FROM users WHERE user_id = 1" }
    .single()

(suspend) fun <T : Any> singleOrNull(returnType: KClass<T>): T?

Receives the results converted to the specified type.

val user: User? = kueyClient
    .sql { +"SELECT * FROM users WHERE user_id = 1" }
    .singleOrNull()

(suspend) fun listMap(): List<Map<String, Any?>>

Receives the results of multiple rows as a map.

val result: List<Map<String, Any?>> = kueyClient
    .sql { +"SELECT * FROM users WHERE user_id = 1" }
    .listMap()

(suspend) fun <T : Any> list(returnType: KClass<T>): List<T>

Receives the results of multiple rows converted to the specified type.

val users: List<User> = kueyClient
    .sql { +"SELECT * FROM users WHERE user_id = 1" }
    .list()

[kuery-client-spring-data-r2dbc only] fun flowMap(): Flow<Map<String, Any?>>

Receives the results of multiple rows as a map.

val result: Flow<Map<String, Any?>> = kueyClient
    .sql { +"SELECT * FROM users WHERE user_id = 1" }
    .flowMap()

[kuery-client-spring-data-r2dbc only] fun <T : Any> flow(returnType: KClass<T>): Flow<T>

Receives the results of multiple rows converted to the specified type.

val users: Flow<User> = kueyClient
    .sql { +"SELECT * FROM users WHERE user_id = 1" }
    .flow()

(suspend) fun rowsUpdated(): Long

Contract for fetching the number of affected rows

val result: Long = kueyClient
    .sql {+"INSERT INTO users (username, email) VALUES ('username1', 'email1')"}
    .rowsUpdated()

(suspend) fun generatedValues(vararg columns: String): Map<String, Any>

Receives the values generated on the database side. For example, an auto increment value.

val result: Map<String, Any> = kueyClient
    .sql {+"INSERT INTO users (username, email) VALUES ('username1', 'email1')"}
    .generatedValues("user_id")