WITH updated_view AS ( UPDATE students SET student_name = '张小立' WHERE id = '08001' ) SELECT * FROM updated_view;第二行的错误

在MySQL中，`WITH`语句用于创建一个临时的结果集，但它并不会直接更改基础表（在这个例子中是`students`表）。你提供的第二行`SELECT * FROM updated_view;`试图从`updated_view`视图中选择所有数据，但这个视图只是一个查询结果的副本，它并没有实际的数据修改功能。

`UPDATE`语句是在`WITH`块内部执行的，表示你尝试在创建视图的过程中对数据进行了更新。然而，当`WITH`块结束时，这些更改不会反映到基础表`students`上，因为视图并不具备直接写入的能力。

如果你想检查是否成功更新了数据，你可以在`UPDATE`语句后使用`SELECT`查询确认`students`表是否有预期的变化。真正的更新动作应该在`WITH`之外执行，比如在事务中，或者在应用服务器上执行。

正确的做法是先执行`UPDATE`语句，然后查询`students`表确认更改：

BEGIN TRANSACTION;
UPDATE students
SET student_name = '张小立'
WHERE id = '08001';
COMMIT;

SELECT * FROM students WHERE id = '08001';

在这里，`BEGIN TRANSACTION`开始了一个事务，`COMMIT`提交事务完成更新，确保了数据的一致性。

相关问题

SELECT COUNT(*) FROM (SELECT t.* from ( SELECT p.*,p.id descId from package_channel_price_plan p as a where a.sys_default=0 UNION SELECT c.*,c.id descId from package_commodity_main_info as b LEFT JOIN package_channel_price_plan as c on b.plan_code=c.plan_code where 1=1 and b.commodity_code = ? ) as t where 1=1 and t.plan_status = ? order by descId=? desc, t.updated_time DESC) TOTAL 这个ssql 错在哪

这个 SQL 语句的错误在于使用了别名 `as a` 和 `as b` 来引用表，但是在子查询中并没有定义这些别名，导致语法错误。正确的写法应该是将别名直接放在子查询的括号后面，而不是在子查询内部的每个表名后面。以下是修正后的 SQL 语句：

SELECT COUNT(*) FROM (
    SELECT t.* 
    FROM (
        SELECT p.*, p.id AS descId 
        FROM package_channel_price_plan p 
        WHERE p.sys_default = 0 
        
        UNION 
        
        SELECT c.*, c.id AS descId 
        FROM package_commodity_main_info b 
        LEFT JOIN package_channel_price_plan c ON b.plan_code = c.plan_code 
        WHERE 1=1 
        AND b.commodity_code = ?
    ) AS t 
    WHERE 1=1 
    AND t.plan_status = ? 
    ORDER BY descId DESC, t.updated_time DESC
) AS TOTAL

update equipment_entity set number = 2 where（select equipment_id from well_entity where delflag = 0 and name = '井2') ;

Unfortunately, as an AI language model, I cannot determine the exact context and structure of your database tables. However, based on the query you provided, it seems that you are trying to update the 'number' field in the 'equipment_entity' table with a value of 2 where the 'equipment_id' from the 'well_entity' table matches a certain condition.

The query you provided is incomplete as it lacks the condition to match the 'equipment_id' from the 'well_entity' table. Here's an updated query that might work:

UPDATE equipment_entity
SET number = 2
WHERE equipment_id IN (
SELECT equipment_id
FROM well_entity
WHERE delflag = 0 AND name = '井2'
);

This query will update the 'number' field in the 'equipment_entity' table to 2 for all records where the 'equipment_id' is found in the subquery that selects the 'equipment_id' from the 'well_entity' table that satisfies the condition 'delflag = 0' and 'name = '井2''.

Please note that the syntax and conditions used in the query may vary depending on the structure of your database tables, so it's best to double-check the table names and column names before running the query.