diff --git a/src/sql/parser.ts b/src/sql/parser.ts
index 32593d9..237430e 100644
--- a/src/sql/parser.ts
+++ b/src/sql/parser.ts
@@ -776,24 +776,48 @@ export class Parser {
   //  条件表达式
   // ===================================================================
 
-  /** condition → simple_cond ((AND|OR) simple_cond)* */
+  /**
+   * condition → or_expr
+   *
+   * v0.8.0 根治：AND 的优先级必须高于 OR（SQL 标准）。
+   *
+   * 此前实现是**纯左折叠**的单层循环：
+   *   `a = 1 OR a = 2 AND b = 3`  →  `(a = 1 OR a = 2) AND b = 3`   ← 错
+   * 标准语义应为：
+   *   `a = 1 OR a = 2 AND b = 3`  →  `a = 1 OR (a = 2 AND b = 3)`   ← 对
+   *
+   * 影响面：任何"权限条件 OR 业务条件 AND 软删标记"的写法都会静默返回错误行集
+   * （审计实测：4 行表上返回 1 行而非 3 行）。这是本层影响面最大、改动最小的缺陷。
+   *
+   * 现在按标准文法分层：or_expr → and_expr (OR and_expr)*
+   *                          and_expr → unary (AND unary)*
+   *                          unary   → [NOT] primary
+   * 并且只在**确实有多个操作数**时才包 $and/$or，避免生成 {$and:[x]} 这种冗余节点
+   * （否则 `WHERE a = 1` 的结构会从 `{a:{$eq:1}}` 变成 `{$and:[{a:{$eq:1}}]}`，
+   *  破坏既有 AST 契约与下游引擎的索引下推识别）。
+   */
   private parseCondition(): WhereCondition {
-    let left = this.parseSimpleCondition();
+    return this.parseOrExpression();
+  }
 
-    while (this.curTokenIs(TokenType.AND) || this.curTokenIs(TokenType.OR)) {
-      const isAnd = this.curTokenIs(TokenType.AND);
+  /** or_expr → and_expr (OR and_expr)* */
+  private parseOrExpression(): WhereCondition {
+    const operands: WhereCondition[] = [this.parseAndExpression()];
+    while (this.curTokenIs(TokenType.OR)) {
       this.nextToken();
-      const right = this.parseSimpleCondition();
-
-      if (isAnd) {
-        // 合并到 $and
-        left = { $and: [left, right] } as unknown as WhereCondition;
-      } else {
-        left = { $or: [left, right] } as unknown as WhereCondition;
-      }
+      operands.push(this.parseAndExpression());
     }
+    return operands.length === 1 ? operands[0] : ({ $or: operands } as unknown as WhereCondition);
+  }
 
-    return left;
+  /** and_expr → simple_cond (AND simple_cond)* */
+  private parseAndExpression(): WhereCondition {
+    const operands: WhereCondition[] = [this.parseSimpleCondition()];
+    while (this.curTokenIs(TokenType.AND)) {
+      this.nextToken();
+      operands.push(this.parseSimpleCondition());
+    }
+    return operands.length === 1 ? operands[0] : ({ $and: operands } as unknown as WhereCondition);
   }
 
   /** 公共 WHERE 条件入口（供 CASE WHEN 求值等外部场景，v0.3.1） */