Add group_concat aggregator function

Signed-off-by: Vitor Mattos <vitor@php.rio>

4 files changed, 34 insertions, 0 deletions

diff --git a/lib/private/DB/QueryBuilder/FunctionBuilder/FunctionBuilder.php b/lib/private/DB/QueryBuilder/FunctionBuilder/FunctionBuilder.php
index dfc0d0a6d61..88290237a90 100644
--- a/lib/private/DB/QueryBuilder/FunctionBuilder/FunctionBuilder.php
+++ b/lib/private/DB/QueryBuilder/FunctionBuilder/FunctionBuilder.php
@@ -49,6 +49,10 @@ class FunctionBuilder implements IFunctionBuilder {
 		return new QueryFunction('CONCAT(' . $this->helper->quoteColumnName($x) . ', ' . $this->helper->quoteColumnName($y) . ')');
 	}
 
+	public function groupConcat($expr, ?string $separator = ','): IQueryFunction {
+		return new QueryFunction('GROUP_CONCAT(' . $this->helper->quoteColumnName($expr) . ')');
+	}
+
 	public function substring($input, $start, $length = null): IQueryFunction {
 		if ($length) {
 			return new QueryFunction('SUBSTR(' . $this->helper->quoteColumnName($input) . ', ' . $this->helper->quoteColumnName($start) . ', ' . $this->helper->quoteColumnName($length) . ')');
diff --git a/lib/private/DB/QueryBuilder/FunctionBuilder/OCIFunctionBuilder.php b/lib/private/DB/QueryBuilder/FunctionBuilder/OCIFunctionBuilder.php
index 5581207a166..af72d85d511 100644
--- a/lib/private/DB/QueryBuilder/FunctionBuilder/OCIFunctionBuilder.php
+++ b/lib/private/DB/QueryBuilder/FunctionBuilder/OCIFunctionBuilder.php
@@ -72,4 +72,11 @@ class OCIFunctionBuilder extends FunctionBuilder {
 
 		return parent::least($x, $y);
 	}
+
+	public function groupConcat($expr, ?string $separator = ','): IQueryFunction {
+		if (is_null($separator)) {
+			return new QueryFunction('LISTAGG(' . $this->helper->quoteColumnName($expr));
+		}
+		return new QueryFunction('LISTAGG(' . $this->helper->quoteColumnName($expr) . ", '$separator')");
+	}
 }
diff --git a/lib/private/DB/QueryBuilder/FunctionBuilder/PgSqlFunctionBuilder.php b/lib/private/DB/QueryBuilder/FunctionBuilder/PgSqlFunctionBuilder.php
index 853c65ac32a..a3a25b7e293 100644
--- a/lib/private/DB/QueryBuilder/FunctionBuilder/PgSqlFunctionBuilder.php
+++ b/lib/private/DB/QueryBuilder/FunctionBuilder/PgSqlFunctionBuilder.php
@@ -30,4 +30,11 @@ class PgSqlFunctionBuilder extends FunctionBuilder {
 	public function concat($x, $y): IQueryFunction {
 		return new QueryFunction('(' . $this->helper->quoteColumnName($x) . ' || ' . $this->helper->quoteColumnName($y) . ')');
 	}
+
+	public function groupConcat($expr, ?string $separator = ','): IQueryFunction {
+		if (is_null($separator)) {
+			return new QueryFunction('string_agg(' . $this->helper->quoteColumnName($expr));
+		}
+		return new QueryFunction('string_agg(' . $this->helper->quoteColumnName($expr) . ", '$separator')");
+	}
 }
diff --git a/lib/public/DB/QueryBuilder/IFunctionBuilder.php b/lib/public/DB/QueryBuilder/IFunctionBuilder.php
index 33d0fbe3b1a..e04a4cbfdba 100644
--- a/lib/public/DB/QueryBuilder/IFunctionBuilder.php
+++ b/lib/public/DB/QueryBuilder/IFunctionBuilder.php
@@ -52,6 +52,22 @@ interface IFunctionBuilder {
 	public function concat($x, $y): IQueryFunction;
 
 	/**
+	 * Returns a string which is the concatenation of all non-NULL values of X
+	 *
+	 * Usage examples:
+	 *
+	 * groupConcat('column') -- with comma as separator (default separator)
+	 *
+	 * groupConcat('column', ';') -- with different separator
+	 *
+	 * @param string|ILiteral|IParameter|IQueryFunction $expr The expression to group
+	 * @param string|null $separator The separator
+	 * @return IQueryFunction
+	 * @since 24.0.0
+	 */
+	public function groupConcat($expr, ?string $separator = ','): IQueryFunction;
+
+	/**
 	 * Takes a substring from the input string
 	 *
 	 * @param string|ILiteral|IParameter|IQueryFunction $input The input string