# [FAQ] TiDB SQL 因空格报错 Unknown column 'X' in 'where clause'

## Key Words

Unknown column 'X' in 'where clause', 语法, parser

## Description

1. 使用如下步骤可复现该报错，即：在 schema name 和 table name 之间添加一个空格。  

    ```sql
    CREATE TABLE `t` (
      `status` int(11) DEFAULT NULL
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;
    mysql> select * from t where t. status = 1;
    ERROR 1054 (42S22): Unknown column '1' in 'where clause'
    mysql> select * from t where t.status = 1;
    Empty set (0.01 sec)
    ```

2. 报错堆栈如下所示

    ```
    [2022/05/30 17:15:02.544 +08:00] [INFO] [conn.go:1149] ["command dispatched failed"] [conn=2199023255955]   [connInfo="id:2199023255955, addr:127.0.0.1:52046 status:10, collation:utf8mb4_0900_ai_ci, user:root"] [command=Query]    [status="inTxn:0, autocommit:1"] [sql="select * from t where t. status = 1"] [txn_mode=OPTIMISTIC] [timestamp=0] [err="[planner:1054]  Unknown column '1' in 'where clause'
    github.com/pingcap/errors.AddStack
        /Users/yusp/go/pkg/mod/github.com/pingcap/errors@v0.11.5-0.20211224045212-9687c2b0f87c/errors.go:174
    github.com/pingcap/errors.(*Error).GenWithStackByArgs
        /Users/yusp/go/pkg/mod/github.com/pingcap/errors@v0.11.5-0.20211224045212-9687c2b0f87c/normalize.go:164
    github.com/pingcap/tidb/planner/core.(*expressionRewriter).toColumn
        /Users/yusp/work/tidb/planner/core/expression_rewriter.go:1937
    github.com/pingcap/tidb/planner/core.(*expressionRewriter).Leave
        /Users/yusp/work/tidb/planner/core/expression_rewriter.go:1095
    github.com/pingcap/tidb/parser/ast.(*ColumnName).Accept
        /Users/yusp/work/tidb/parser/ast/expressions.go:534
    github.com/pingcap/tidb/parser/ast.(*ColumnNameExpr).Accept
        /Users/yusp/work/tidb/parser/ast/expressions.go:596
    github.com/pingcap/tidb/parser/ast.(*BinaryOperationExpr).Accept
        /Users/yusp/work/tidb/parser/ast/expressions.go:217
    github.com/pingcap/tidb/planner/core.(*PlanBuilder).rewriteExprNode
        /Users/yusp/work/tidb/planner/core/expression_rewriter.go:199
    github.com/pingcap/tidb/planner/core.(*PlanBuilder).rewriteWithPreprocess
        /Users/yusp/work/tidb/planner/core/expression_rewriter.go:145
    github.com/pingcap/tidb/planner/core.(*PlanBuilder).rewrite
        /Users/yusp/work/tidb/planner/core/expression_rewriter.go:113
    github.com/pingcap/tidb/planner/core.(*PlanBuilder).buildSelection
        /Users/yusp/work/tidb/planner/core/logical_plan_builder.go:992
    github.com/pingcap/tidb/planner/core.(*PlanBuilder).buildSelect
        /Users/yusp/work/tidb/planner/core/logical_plan_builder.go:3864
    github.com/pingcap/tidb/planner/core.(*PlanBuilder).Build
        /Users/yusp/work/tidb/planner/core/planbuilder.go:701
    ```

## Content

这是 TiDB 解析器的一个 BUG，详情见 GitHub Issue ： <https://github.com/pingcap/tidb/issues/35031> 

## Affected Versions

ALL