Allow placeholders in place of ratio expressions in hogql

posthog/hogql/grammar/HogQLLexer.py

@@ -1,4 +1,4 @@
-# Generated from HogQLLexer.g4 by ANTLR 4.13.0
+# Generated from HogQLLexer.g4 by ANTLR 4.13.1
 from antlr4 import *
 from io import StringIO
 import sys
@@ -1252,7 +1252,7 @@ class HogQLLexer(Lexer):
 
     def __init__(self, input=None, output:TextIO = sys.stdout):
         super().__init__(input, output)
-        self.checkVersion("4.13.0")
+        self.checkVersion("4.13.1")
         self._interp = LexerATNSimulator(self, self.atn, self.decisionsToDFA, PredictionContextCache())
         self._actions = None
         self._predicates = None

posthog/hogql/grammar/HogQLParser.g4

@@ -70,7 +70,7 @@ joinConstraintClause
 sampleClause: SAMPLE ratioExpr (OFFSET ratioExpr)?;
 orderExprList: orderExpr (COMMA orderExpr)*;
 orderExpr: columnExpr (ASCENDING | DESCENDING | DESC)? (NULLS (FIRST | LAST))? (COLLATE STRING_LITERAL)?;
-ratioExpr: numberLiteral (SLASH numberLiteral)?;
+ratioExpr: PLACEHOLDER | numberLiteral (SLASH numberLiteral)?;
 settingExprList: settingExpr (COMMA settingExpr)*;
 settingExpr: identifier EQ_SINGLE literal;
 

posthog/hogql/grammar/HogQLParserVisitor.py

@@ -1,4 +1,4 @@
-# Generated from HogQLParser.g4 by ANTLR 4.13.0
+# Generated from HogQLParser.g4 by ANTLR 4.13.1
 from antlr4 import *
 if "." in __name__:
     from .HogQLParser import HogQLParser

posthog/hogql/parser.py

@@ -363,6 +363,9 @@ def visitOrderExpr(self, ctx: HogQLParser.OrderExprContext):
         return ast.OrderExpr(expr=self.visit(ctx.columnExpr()), order=cast(Literal["ASC", "DESC"], order))
 
     def visitRatioExpr(self, ctx: HogQLParser.RatioExprContext):
+        if ctx.PLACEHOLDER():
+            return ast.Placeholder(field=parse_string_literal(ctx.PLACEHOLDER()))
+
         number_literals = ctx.numberLiteral()
 
         left = number_literals[0]

posthog/hogql_queries/insights/trends/query_builder.py

@@ -104,15 +104,15 @@ def _get_events_subquery(self) -> ast.SelectQuery:
                     {aggregation_operation} AS total,
                     dateTrunc({interval}, toTimeZone(toDateTime(timestamp), 'UTC')) AS day_start
                 FROM events AS e
-                %s
+                SAMPLE {sample}
                 WHERE {events_filter}
                 GROUP BY day_start
-            """
-            % (self._sample_value()),
+            """,
             placeholders={
                 **self.query_date_range.to_placeholders(),
                 "events_filter": self._events_filter(),
                 "aggregation_operation": self._aggregation_operation(),
+                "sample": self._sample_value(),
             },
         )
 
@@ -223,9 +223,9 @@ def _aggregation_operation(self) -> ast.Expr:
     # Using string interpolation for SAMPLE due to HogQL limitations with `UNION ALL` and `SAMPLE` AST nodes
     def _sample_value(self) -> str:
         if self.query.samplingFactor is None:
-            return ""
+            return ast.RatioExpr(left=ast.Constant(value=1))
 
-        return f"SAMPLE {self.query.samplingFactor}"
+        return ast.RatioExpr(left=ast.Constant(value=self.query.samplingFactor))
 
     @cached_property
     def _breakdown(self):