JetBrains#623 Add support of window functions in Exposed DSL (JetBrai…

…ns#1651) * JetBrains#623 Add support of window functions in Exposed DSL -Support of partition by and order by clauses -Support of window frame clause (without EXCLUDE) -Factories for common window functions -Support for using aggregate functions as window functions * JetBrains#623 Fix linter warnings * Better name for NthValue class 'index' argument Change argument to 'n' to conform with the most DB docs Co-authored-by: Jocelyne <38375996+joc-a@users.noreply.github.com> * Better name for nthValue function 'index' argument Change argument to 'n' to conform with the most DB docs Co-authored-by: Jocelyne <38375996+joc-a@users.noreply.github.com> * JetBrains#623 Refactor window function definition Window function definitions moved from top-level to ISqlExpressionBuilder to eliminate their irrelevant appearance in code completion. * JetBrains#623 Dump window functions related API changes * JetBrains#623 Fix smart cast warning by replacing not-null assertion with null-safe call * JetBrains#623 remove redundant DatabaseDialect.supportsWindowFunctions This flag was used only in tests. Its value was false only for MySql < 8 which is covered by DatabaseTestsBase.kt Transaction.isOldMySql --------- Co-authored-by: Dmitry Levin <dlevin@anylogic.com> Co-authored-by: Jocelyne <38375996+joc-a@users.noreply.github.com>
saral · Oct 3, 2023 · 1afe347 · 1afe347
1 parent 4ec9b96
commit 1afe347
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Showing 10 changed files with 1,292 additions and 19 deletions.
diff --git a/exposed-core/api/exposed-core.api b/exposed-core/api/exposed-core.api
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
@@ -163,8 +163,12 @@ class Min<T : Comparable<T>, in S : T?>(
     /** Returns the expression from which the minimum value is obtained. */
     val expr: Expression<in S>,
     columnType: IColumnType
-) : Function<T?>(columnType) {
+) : Function<T?>(columnType), WindowFunction<T?> {
     override fun toQueryBuilder(queryBuilder: QueryBuilder): Unit = queryBuilder { append("MIN(", expr, ")") }
+
+    override fun over(): WindowFunctionDefinition<T?> {
+        return WindowFunctionDefinition(columnType, this)
+    }
 }
 
 /**
@@ -174,8 +178,12 @@ class Max<T : Comparable<T>, in S : T?>(
     /** Returns the expression from which the maximum value is obtained. */
     val expr: Expression<in S>,
     columnType: IColumnType
-) : Function<T?>(columnType) {
+) : Function<T?>(columnType), WindowFunction<T?> {
     override fun toQueryBuilder(queryBuilder: QueryBuilder): Unit = queryBuilder { append("MAX(", expr, ")") }
+
+    override fun over(): WindowFunctionDefinition<T?> {
+        return WindowFunctionDefinition(columnType, this)
+    }
 }
 
 /**
@@ -185,8 +193,12 @@ class Avg<T : Comparable<T>, in S : T?>(
     /** Returns the expression from which the average is calculated. */
     val expr: Expression<in S>,
     scale: Int
-) : Function<BigDecimal?>(DecimalColumnType(Int.MAX_VALUE, scale)) {
+) : Function<BigDecimal?>(DecimalColumnType(Int.MAX_VALUE, scale)), WindowFunction<BigDecimal?> {
     override fun toQueryBuilder(queryBuilder: QueryBuilder): Unit = queryBuilder { append("AVG(", expr, ")") }
+
+    override fun over(): WindowFunctionDefinition<BigDecimal?> {
+        return WindowFunctionDefinition(columnType, this)
+    }
 }
 
 /**
@@ -196,8 +208,12 @@ class Sum<T>(
     /** Returns the expression from which the sum is calculated. */
     val expr: Expression<T>,
     columnType: IColumnType
-) : Function<T?>(columnType) {
+) : Function<T?>(columnType), WindowFunction<T?> {
     override fun toQueryBuilder(queryBuilder: QueryBuilder): Unit = queryBuilder { append("SUM(", expr, ")") }
+
+    override fun over(): WindowFunctionDefinition<T?> {
+        return WindowFunctionDefinition(columnType, this)
+    }
 }
 
 /**
@@ -208,13 +224,17 @@ class Count(
     val expr: Expression<*>,
     /** Returns whether only distinct element should be count. */
     val distinct: Boolean = false
-) : Function<Long>(LongColumnType()) {
+) : Function<Long>(LongColumnType()), WindowFunction<Long> {
     override fun toQueryBuilder(queryBuilder: QueryBuilder): Unit = queryBuilder {
         +"COUNT("
         if (distinct) +"DISTINCT "
         +expr
         +")"
     }
+
+    override fun over(): WindowFunctionDefinition<Long> {
+        return WindowFunctionDefinition(LongColumnType(), this)
+    }
 }
 
 // Aggregate Functions for Statistics
@@ -227,7 +247,7 @@ class StdDevPop<T>(
     /** Returns the expression from which the population standard deviation is calculated. */
     val expression: Expression<T>,
     scale: Int
-) : Function<BigDecimal?>(DecimalColumnType(Int.MAX_VALUE, scale)) {
+) : Function<BigDecimal?>(DecimalColumnType(Int.MAX_VALUE, scale)), WindowFunction<BigDecimal?> {
     override fun toQueryBuilder(queryBuilder: QueryBuilder) {
         queryBuilder {
             val functionProvider = when (currentDialect.h2Mode) {
@@ -237,6 +257,10 @@ class StdDevPop<T>(
             functionProvider.stdDevPop(expression, this)
         }
     }
+
+    override fun over(): WindowFunctionDefinition<BigDecimal?> {
+        return WindowFunctionDefinition(columnType, this)
+    }
 }
 
 /**
@@ -247,7 +271,7 @@ class StdDevSamp<T>(
     /** Returns the expression from which the sample standard deviation is calculated. */
     val expression: Expression<T>,
     scale: Int
-) : Function<BigDecimal?>(DecimalColumnType(Int.MAX_VALUE, scale)) {
+) : Function<BigDecimal?>(DecimalColumnType(Int.MAX_VALUE, scale)), WindowFunction<BigDecimal?> {
     override fun toQueryBuilder(queryBuilder: QueryBuilder) {
         queryBuilder {
             val functionProvider = when (currentDialect.h2Mode) {
@@ -257,6 +281,10 @@ class StdDevSamp<T>(
             functionProvider.stdDevSamp(expression, this)
         }
     }
+
+    override fun over(): WindowFunctionDefinition<BigDecimal?> {
+        return WindowFunctionDefinition(columnType, this)
+    }
 }
 
 /**
@@ -267,7 +295,7 @@ class VarPop<T>(
     /** Returns the expression from which the population variance is calculated. */
     val expression: Expression<T>,
     scale: Int
-) : Function<BigDecimal?>(DecimalColumnType(Int.MAX_VALUE, scale)) {
+) : Function<BigDecimal?>(DecimalColumnType(Int.MAX_VALUE, scale)), WindowFunction<BigDecimal?> {
     override fun toQueryBuilder(queryBuilder: QueryBuilder) {
         queryBuilder {
             val functionProvider = when (currentDialect.h2Mode) {
@@ -277,6 +305,10 @@ class VarPop<T>(
             functionProvider.varPop(expression, this)
         }
     }
+
+    override fun over(): WindowFunctionDefinition<BigDecimal?> {
+        return WindowFunctionDefinition(columnType, this)
+    }
 }
 
 /**
@@ -287,7 +319,7 @@ class VarSamp<T>(
     /** Returns the expression from which the sample variance is calculated. */
     val expression: Expression<T>,
     scale: Int
-) : Function<BigDecimal?>(DecimalColumnType(Int.MAX_VALUE, scale)) {
+) : Function<BigDecimal?>(DecimalColumnType(Int.MAX_VALUE, scale)), WindowFunction<BigDecimal?> {
     override fun toQueryBuilder(queryBuilder: QueryBuilder) {
         queryBuilder {
             val functionProvider = when (currentDialect.h2Mode) {
@@ -297,6 +329,10 @@ class VarSamp<T>(
             functionProvider.varSamp(expression, this)
         }
     }
+
+    override fun over(): WindowFunctionDefinition<BigDecimal?> {
+        return WindowFunctionDefinition(columnType, this)
+    }
 }
 
 // JSON Functions
@@ -325,7 +361,7 @@ class JsonExtract<T>(
 /**
  * Represents an SQL function that advances the specified [seq] and returns the new value.
  */
-sealed class NextVal<T> (
+sealed class NextVal<T>(
     /** Returns the sequence from which the next value is obtained. */
     val seq: Sequence,
     columnType: IColumnType

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
@@ -526,6 +526,68 @@ interface ISqlExpressionBuilder {
         caseSensitive: Boolean = true
     ): RegexpOp<T> = RegexpOp(this, pattern, caseSensitive)
 
+    // Window Functions
+
+    /** Returns the number of the current row within its partition, counting from 1. */
+    fun rowNumber(): RowNumber = RowNumber()
+
+    /** Returns the rank of the current row, with gaps; that is, the row_number of the first row in its peer group. */
+    fun rank(): Rank = Rank()
+
+    /** Returns the rank of the current row, without gaps; this function effectively counts peer groups. */
+    fun denseRank(): DenseRank = DenseRank()
+
+    /**
+     * Returns the relative rank of the current row, that is (rank - 1) / (total partition rows - 1).
+     * The value thus ranges from 0 to 1 inclusive.
+     */
+    fun percentRank(): PercentRank = PercentRank()
+
+    /**
+     * Returns the cumulative distribution, that is (number of partition rows preceding or peers with current row) /
+     * (total partition rows). The value thus ranges from 1/N to 1.
+     */
+    fun cumeDist(): CumeDist = CumeDist()
+
+    /** Returns an integer ranging from 1 to the [numBuckets], dividing the partition as equally as possible. */
+    fun ntile(numBuckets: ExpressionWithColumnType<Int>): Ntile = Ntile(numBuckets)
+
+    /**
+     * Returns value evaluated at the row that is [offset] rows before the current row within the partition;
+     * if there is no such row, instead returns [defaultValue].
+     * Both [offset] and [defaultValue] are evaluated with respect to the current row.
+     */
+    fun <T> ExpressionWithColumnType<T>.lag(
+        offset: ExpressionWithColumnType<Int> = intLiteral(1),
+        defaultValue: ExpressionWithColumnType<T>? = null
+    ): Lag<T> = Lag(this, offset, defaultValue)
+
+    /**
+     * Returns value evaluated at the row that is [offset] rows after the current row within the partition;
+     * if there is no such row, instead returns [defaultValue].
+     * Both [offset] and [defaultValue] are evaluated with respect to the current row.
+     */
+    fun <T> ExpressionWithColumnType<T>.lead(
+        offset: ExpressionWithColumnType<Int> = intLiteral(1),
+        defaultValue: ExpressionWithColumnType<T>? = null
+    ): Lead<T> = Lead(this, offset, defaultValue)
+
+    /**
+     * Returns value evaluated at the row that is the first row of the window frame.
+     */
+    fun <T> ExpressionWithColumnType<T>.firstValue(): FirstValue<T> = FirstValue(this)
+
+    /**
+     * Returns value evaluated at the row that is the last row of the window frame.
+     */
+    fun <T> ExpressionWithColumnType<T>.lastValue(): LastValue<T> = LastValue(this)
+
+    /**
+     * Returns value evaluated at the row that is the [n]'th row of the window frame
+     * (counting from 1); null if no such row.
+     */
+    fun <T> ExpressionWithColumnType<T>.nthValue(n: ExpressionWithColumnType<Int>): NthValue<T> = NthValue(this, n)
+
     // JSON Conditions
 
     /**