(superset) branch pinot-substr created (now 3482fcb53c)

[be...@apache.org]

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beto pushed a change to branch pinot-substr
in repository https://gitbox.apache.org/repos/asf/superset.git


      at 3482fcb53c fix(pinot): `SUBSTR` function

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     new 3482fcb53c fix(pinot): `SUBSTR` function

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(superset) 01/01: fix(pinot): `SUBSTR` function

[be...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

beto pushed a commit to branch pinot-substr
in repository https://gitbox.apache.org/repos/asf/superset.git

commit 3482fcb53cb02dbbcf8c17e883c0131dbbb2344e
Author: Beto Dealmeida <ro...@dealmeida.net>
AuthorDate: Wed Oct 1 17:10:15 2025 -0400

    fix(pinot): `SUBSTR` function
---
 superset/sql/dialects/pinot.py               |  6 ++++++
 tests/unit_tests/sql/dialects/pinot_tests.py | 22 ++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/superset/sql/dialects/pinot.py b/superset/sql/dialects/pinot.py
index ff7427288e..a379006fba 100644
--- a/superset/sql/dialects/pinot.py
+++ b/superset/sql/dialects/pinot.py
@@ -108,6 +108,12 @@ class Pinot(MySQL):
                 e.args.get("expression"),
                 e.this,
             ),
+            exp.Substring: lambda self, e: self.func(
+                "SUBSTR",
+                e.this,
+                e.args.get("start"),
+                e.args.get("length"),
+            ),
         }
         # Remove DATE_TRUNC transformation - Pinot supports standard SQL DATE_TRUNC
         TRANSFORMS.pop(exp.DateTrunc, None)
diff --git a/tests/unit_tests/sql/dialects/pinot_tests.py b/tests/unit_tests/sql/dialects/pinot_tests.py
index db05b281f8..22ee406ae6 100644
--- a/tests/unit_tests/sql/dialects/pinot_tests.py
+++ b/tests/unit_tests/sql/dialects/pinot_tests.py
@@ -562,3 +562,25 @@ def test_pinot_date_sub_simple() -> None:
         # Verify that it generates valid SQL
         generated = parsed.sql(dialect=Pinot)
         assert "DATE_SUB" in generated.upper()
+
+
+def test_substr_cross_dialect_generation() -> None:
+    """
+    Test that SUBSTR is preserved when generating Pinot SQL.
+
+    Note that the MySQL dialect (in which Pinot is based) uses SUBSTRING instead of
+    SUBSTR.
+    """
+    # Parse with Pinot dialect
+    pinot_sql = "SELECT SUBSTR('hello', 0, 3) FROM users"
+    parsed = sqlglot.parse_one(pinot_sql, Pinot)
+
+    # Generate back to Pinot → should preserve SUBSTR
+    pinot_output = parsed.sql(dialect=Pinot)
+    assert "SUBSTR(" in pinot_output
+    assert "SUBSTRING(" not in pinot_output
+
+    # Generate to MySQL → should convert to SUBSTRING
+    mysql_output = parsed.sql(dialect="mysql")
+    assert "SUBSTRING(" in mysql_output
+    assert pinot_output != mysql_output  # They should be different