请提供简单的SQL语法帮助

Question

我用这个把我的头撞在墙上。为什么SSMS中的查询编辑器在此查询末尾给我一个关于右括号的错误？

    SELECT 
        c.TABLE_NAME,
        c.COLUMN_NAME
    FROM INFORMATION_SCHEMA.COLUMNS c
    INNER JOIN 
        (SELECT 
            COLUMN_NAME
        FROM INFORMATION_SCHEMA.COLUMNS
        GROUP BY COLUMN_NAME
        HAVING COUNT(*) = 1
        )

Incorrect syntax near ')'.

Answer 1

您在括号中缺少子查询的别名和on子句：

SELECT 
    c.TABLE_NAME,
    c.COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS c
INNER JOIN 
    (SELECT 
        COLUMN_NAME
    FROM INFORMATION_SCHEMA.COLUMNS
    GROUP BY COLUMN_NAME
    HAVING COUNT(*) = 1
    ) x -- Alias added here
    ON x.COLUMN_NAME = c.COLUMN_NAME -- ON caluse

Answer 2

您无需在此处使用join，您可以使用exists：

select c.*
from information_schema.columns c
where not exists (select 1 
                  from information_schema.columns c1
                  where (c1.column_name = c.column_name) and
                        (c1.table_name <> c.table_name or c1.table_schema <> c.table_schema)
                );