解释一下以下代码： '%3bselect case when (1=1) then pg_sleep(10) else pg_sleep(0) end --

这段代码是一个针对 PostgreSQL 数据库的注入攻击的示例。让我来解释一下每个部分的含义：

- `%3b`: 这是 URL 编码中分号（;）的编码形式。它用于分隔不同的 SQL 语句，使得注入攻击可以在同一个查询中执行多个语句。

- `select case when (1=1) then pg_sleep(10) else pg_sleep(0) end`: 这是一个条件语句，用于在查询中执行延时函数 `pg_sleep()`。如果条件 `(1=1)` 成立，将执行 `pg_sleep(10)` 函数，即暂停 10 秒钟；否则执行 `pg_sleep(0)` 函数，即不进行延时。

- `--`: 这是 SQL 注释符号，用于注释掉代码行的剩余部分，使得后续的代码不会被执行。在这个示例中，它用于注释掉可能存在的其他代码。

综上所述，这段代码的目的是通过注入到查询中，利用条件语句和延时函数来判断条件是否成立，并实现延时效果。如果条件成立，则会执行 `pg_sleep(10)` 函数，导致查询延时 10 秒钟。

需要注意的是，这段代码是一种恶意注入攻击，可能会导致数据库安全问题。在实际应用中，务必对用户输入进行严格验证和过滤，以避免注入攻击。同时，及时更新和修补数据库系统，以确保安全性。

相关问题

用 case when 写一个733：过滤条件： pause_day = 1，channel = 2 734 : 过滤条件： pause_day = 7，channel = 2 735 : 过滤条件： pause_day = 1，channel = 1 736 : 过滤条件： pause_day = 7，channel = 1 798 : 过滤条件： pause_day = 1，channel = 3 799 : 过滤条件： pause_day = 7，channel = 3的查询语句

733:

SELECT *
FROM table_name
WHERE
    CASE WHEN pause_day = 1 AND channel = 2 THEN 1 ELSE 0 END = 1;

734:

SELECT *
FROM table_name
WHERE
    CASE WHEN pause_day = 7 AND channel = 2 THEN 1 ELSE 0 END = 1;

735:

SELECT *
FROM table_name
WHERE
    CASE WHEN pause_day = 1 AND channel = 1 THEN 1 ELSE 0 END = 1;

736:

SELECT *
FROM table_name
WHERE
    CASE WHEN pause_day = 7 AND channel = 1 THEN 1 ELSE 0 END = 1;

798:

SELECT *
FROM table_name
WHERE
    CASE WHEN pause_day = 1 AND channel = 3 THEN 1 ELSE 0 END = 1;

799:

SELECT *
FROM table_name
WHERE
    CASE WHEN pause_day = 7 AND channel = 3 THEN 1 ELSE 0 END = 1;

你能把pg视图改为sqlserver的视图吗 SELECT c.relname AS table_name, a.attname AS column_name, d.description AS column_comment, CASE WHEN a.attnotnull AND con.conname IS NULL THEN 1 ELSE 0 END AS is_required, CASE WHEN con.conname IS NOT NULL THEN 1 ELSE 0 END AS is_pk, a.attnum AS sort, CASE WHEN "position"(pg_get_expr(ad.adbin, ad.adrelid), ((c.relname::text || '_'::text) || a.attname::text) || '_seq'::text) > 0 THEN 1 ELSE 0 END AS is_increment, btrim( CASE WHEN t.typelem <> 0::oid AND t.typlen = '-1'::integer THEN 'ARRAY'::text ELSE CASE WHEN t.typtype = 'd'::"char" THEN format_type(t.typbasetype, NULL::integer) ELSE format_type(a.atttypid, NULL::integer) END END, '"'::text) AS column_type FROM pg_attribute a JOIN (pg_class c JOIN pg_namespace n ON c.relnamespace = n.oid) ON a.attrelid = c.oid LEFT JOIN pg_description d ON d.objoid = c.oid AND a.attnum = d.objsubid LEFT JOIN pg_constraint con ON con.conrelid = c.oid AND (a.attnum = ANY (con.conkey)) LEFT JOIN pg_attrdef ad ON a.attrelid = ad.adrelid AND a.attnum = ad.adnum LEFT JOIN pg_type t ON a.atttypid = t.oid WHERE (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND a.attnum > 0 AND n.nspname = 'public'::name ORDER BY c.relname, a.attnum

抱歉，我无法将此查询转换为SQL Server的视图。这是因为该查询涉及到了一些PostgreSQL特定的函数和表达式，这些在SQL Server中并不存在。你可能需要手动重新编写查询以适应SQL Server的语法和函数。以下是一个可能的SQL Server等效查询的示例，供参考：

SELECT 
    t.name AS table_name,
    c.name AS column_name,
    CAST(ep.value AS NVARCHAR(MAX)) AS column_comment,
    CASE
        WHEN c.is_nullable = 0 AND pk.constraint_column_id IS NULL THEN 1
        ELSE 0
    END AS is_required,
    CASE
        WHEN pk.constraint_column_id IS NOT NULL THEN 1
        ELSE 0
    END AS is_pk,
    c.column_id AS sort,
    CASE
        WHEN COLUMNPROPERTY(c.object_id, c.name, 'IsIdentity') = 1 THEN 1
        ELSE 0
    END AS is_increment,
    CASE
        WHEN t.name = 'varchar' AND c.max_length <> -1 THEN t.name + '(' + CAST(c.max_length AS NVARCHAR(MAX)) + ')'
        WHEN t.name = 'nvarchar' AND c.max_length <> -1 THEN t.name + '(' + CAST(c.max_length / 2 AS NVARCHAR(MAX)) + ')'
        ELSE t.name
    END AS column_type
FROM sys.tables t
INNER JOIN sys.columns c ON t.object_id = c.object_id
LEFT JOIN sys.extended_properties ep ON ep.major_id = t.object_id AND ep.minor_id = c.column_id AND ep.name = 'MS_Description'
LEFT JOIN sys.indexes i ON t.object_id = i.object_id AND i.is_primary_key = 1
LEFT JOIN sys.index_columns ic ON i.object_id = ic.object_id AND i.index_id = ic.index_id AND c.column_id = ic.column_id
LEFT JOIN sys.key_constraints pk ON t.object_id = pk.parent_object_id AND ic.index_column_id = pk.unique_index_id
WHERE t.type = 'U'
AND SCHEMA_NAME(t.schema_id) = 'dbo'
ORDER BY t.name, c.column_id

请注意，这只是一个示例查询，具体取决于你的数据库结构和需求，你可能需要进行一些调整和修改。建议在转换之前备份你的数据库，以防出现意外情况。