### Question:
PostgresSupport { @Support({SQLDialect.POSTGRES}) public static Field<String> stringAgg(Field<String> field, String delimiter) { return DSL.field("string_agg({0}, {1})", field.getDataType(), field, DSL.val(delimiter)); } private  PostgresSupport(); @Support({SQLDialect.POSTGRES}) static Field<T[]> arrayAgg(Field<T> field); @Support({SQLDialect.POSTGRES}) static Field<T[]> arrayAggNoNulls(Field<T> field); @Support({SQLDialect.POSTGRES}) static Field<String> stringAgg(Field<String> field, String delimiter);  }### Answer:
@Test public void joinsStringsWithGivenDelimiter() { Field<String> agg = PostgresSupport.stringAgg(Table1.FIELD_NAME1, ":"); String columnName = Table1.FIELD_NAME1.toString(); assertThat(agg.toString()).isEqualTo("string_agg(" + columnName + ", ':')"); }