Fix: preserve ARRAY_JOIN for StarRocks, Doris (fixes #5095)

Author: georgesittas

sqlglot/dialects/doris.py

@@ -59,6 +59,7 @@ class Generator(MySQL.Generator):
             exp.ArgMax: rename_func("MAX_BY"),
             exp.ArgMin: rename_func("MIN_BY"),
             exp.ArrayAgg: rename_func("COLLECT_LIST"),
+            exp.ArrayToString: rename_func("ARRAY_JOIN"),
             exp.ArrayUniqueAgg: rename_func("COLLECT_SET"),
             exp.CurrentTimestamp: lambda self, _: self.func("NOW"),
             exp.DateTrunc: lambda self, e: self.func("DATE_TRUNC", e.this, unit_to_str(e)),

sqlglot/dialects/starrocks.py

@@ -132,6 +132,7 @@ class Generator(MySQL.Generator):
         TRANSFORMS = {
             **MySQL.Generator.TRANSFORMS,
             exp.Array: inline_array_sql,
+            exp.ArrayToString: rename_func("ARRAY_JOIN"),
             exp.ApproxDistinct: approx_count_distinct_sql,
             exp.DateDiff: lambda self, e: self.func(
                 "DATE_DIFF", unit_to_str(e), e.this, e.expression

tests/dialects/test_starrocks.py

@@ -6,6 +6,8 @@ class TestStarrocks(Validator):
     dialect = "starrocks"
 
     def test_starrocks(self):
+        self.validate_identity("SELECT ARRAY_JOIN([1, 3, 5, NULL], '_', 'NULL')")
+        self.validate_identity("SELECT ARRAY_JOIN([1, 3, 5, NULL], '_')")
         self.validate_identity("ALTER TABLE a SWAP WITH b")
 
     def test_ddl(self):