Make coalesce support multiple arguments #1352 / Fixes and improvements

JetBrains · Oct 25, 2021 · 4fcb50b · 4fcb50b
1 parent fb8d322
commit 4fcb50b
Show file tree

Hide file tree

Showing 3 changed files with 25 additions and 8 deletions.
diff --git a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Function.kt b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Function.kt
@@ -300,11 +300,13 @@ class CaseWhenElse<T, R : T>(val caseWhen: CaseWhen<T>, val elseResult: Expressi
 /**
  * Represents an SQL function that returns the first of its arguments that is not null.
  */
-class Coalesce<out T>(
- private vararg val expressions: ExpressionWithColumnType<T?>,
-) : Function<R>(expressions.first().columnType) {
+class Coalesce<out T, S : T?, R : T>(
+ private val expr: ExpressionWithColumnType<S>,
+ private val alternate: Expression<out T>,
+ private vararg val others: Expression<out T>
+) : Function<R>(expr.columnType) {
  override fun toQueryBuilder(queryBuilder: QueryBuilder): Unit = queryBuilder {
- expressions.toList().appendTo(
+ (listOf(expr, alternate) + others).appendTo(
  prefix = "COALESCE(",
  postfix = ")",
  separator = ", "

diff --git a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/SQLExpressionBuilder.kt b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/SQLExpressionBuilder.kt
@@ -364,8 +364,11 @@ interface ISqlExpressionBuilder {
  // Conditional Expressions
 
  /** Returns the first of its arguments that is not null. */
- fun <T, S : T?, E : ExpressionWithColumnType<S>, R : T> coalesce(expr: E, alternate: ExpressionWithColumnType<out T>): Coalesce<T?, S, R> =
- Coalesce(expr, alternate)
+ fun <T, S : T?, A : Expression<out T>, R : T> coalesce(
+ expr: ExpressionWithColumnType<S>,
+ alternate: A,
+ vararg others: A
+ ): Coalesce<T?, S, R> = Coalesce(expr, alternate, others = others)
 
  fun case(value: Expression<*>? = null): Case = Case(value)
 

diff --git a/...-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/shared/functions/FunctionsTests.kt b/...-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/shared/functions/FunctionsTests.kt
@@ -427,10 +427,22 @@ class FunctionsTests : DatabaseTestsBase() {
 
  users.slice(users.cityId, coalesceExp1).selectAll().forEach {
  val cityId = it[users.cityId]
- if (cityId != null)
+ if (cityId != null) {
  assertEquals(cityId, it[coalesceExp1])
- else
+ } else {
  assertEquals(1000, it[coalesceExp1])
+ }
+ }
+
+ val coalesceExp2 = Coalesce(users.cityId, Op.nullOp<Int>(), intLiteral(1000))
+
+ users.slice(users.cityId, coalesceExp2).selectAll().forEach {
+ val cityId = it[users.cityId]
+ if (cityId != null) {
+ assertEquals(cityId, it[coalesceExp2])
+ } else {
+ assertEquals(1000, it[coalesceExp2])
+ }
  }
  }
  }