refactor: fix ops.StrStripOp

Author: chelsea-lin

bigframes/core/compile/sqlglot/expressions/string_ops.py

@@ -243,7 +243,7 @@ def to_startswith(pat: str) -> sge.Expression:
 
 @register_unary_op(ops.StrStripOp, pass_op=True)
 def _(expr: TypedExpr, op: ops.StrStripOp) -> sge.Expression:
-    return sge.Trim(this=sge.convert(op.to_strip), expression=expr.expr)
+    return sge.Trim(this=expr.expr, expression=sge.convert(op.to_strip))
 
 
 @register_unary_op(ops.StringSplitOp, pass_op=True)

tests/unit/core/compile/sqlglot/expressions/snapshots/test_string_ops/test_strip/out.sql

@@ -5,7 +5,7 @@ WITH `bfcte_0` AS (
 ), `bfcte_1` AS (
   SELECT
     *,
-    TRIM(' ', `string_col`) AS `bfcol_1`
+    TRIM(`string_col`, ' ') AS `bfcol_1`
   FROM `bfcte_0`
 )
 SELECT