From 5e1767dcf642f7b8cc752a2950e142a5da8f19a8 Mon Sep 17 00:00:00 2001
From: Peter Nelson <peter@fuzzle.org>
Date: Sat, 22 Oct 2022 01:17:32 +0100
Subject: [PATCH] Reuse expression parameter if value has already been seen.

This works in the same way for SqlExpression evaluation as SqlBuilder's
ReuseParameters, except it is always on.
---
 src/NPoco/Expressions/SqlExpression.cs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/NPoco/Expressions/SqlExpression.cs b/src/NPoco/Expressions/SqlExpression.cs
index fd810da3..44aac018 100644
--- a/src/NPoco/Expressions/SqlExpression.cs
+++ b/src/NPoco/Expressions/SqlExpression.cs
@@ -1092,6 +1092,11 @@ protected virtual object VisitConditional(ConditionalExpression conditional)
 
         protected string CreateParam(object value)
         {
+            // If value has already been provided, reuse the parameter.
+            var indexOfExistingValue = _params.IndexOf(value);
+            if (indexOfExistingValue >= 0)
+                return paramPrefix + indexOfExistingValue;
+
             string paramPlaceholder = paramPrefix + _params.Count;
             _params.Add(value);
             return paramPlaceholder;