fix bug in Condition::add where Condition negation is ignored

src/query/condition.rs

@@ -46,6 +46,24 @@ impl Condition {
     ///
     /// If it's an [`Condition::any`], it will be separated from the others by an `" OR "` in the query. If it's
     /// an [`Condition::all`], it will be separated by an `" AND "`.
+    ///
+    /// ```
+    /// use sea_query::{*, tests_cfg::*};
+    ///
+    /// let statement = sea_query::Query::select()
+    ///     .column(Glyph::Id)
+    ///     .from(Glyph::Table)
+    ///     .cond_where(
+    ///         Cond::all()
+    ///             .add(Expr::col(Glyph::Aspect).eq(0).into_condition().not())
+    ///             .add(Expr::col(Glyph::Id).eq(0).into_condition().not()),
+    ///     )
+    ///     .to_string(PostgresQueryBuilder);
+    /// assert_eq!(
+    ///     statement,
+    ///     r#"SELECT "id" FROM "glyph" WHERE (NOT ("aspect" = 0)) AND (NOT ("id" = 0))"#
+    /// );
+    /// ```
     #[allow(clippy::should_implement_trait)]
     pub fn add<C>(mut self, condition: C) -> Self
     where
@@ -58,7 +76,7 @@ impl Condition {
                 return self;
             }
             // Skip the junction if there is only one.
-            if c.conditions.len() == 1 {
+            if c.conditions.len() == 1 && !c.negate {
                 expr = c.conditions.pop().unwrap();
             }
         }