In this aricle we are going to see how we can insert NULL values in place of an empty string in MySQL/MariaDB. For the examples in this article, let's assume that: We have a user table with three colum
id` int(10) NOT NULL AUTO_INCREMENT COMMENT '主键ID', -> `uniq_flag` varchar(64) NOT NULL DEFAULT ''COMMENT '唯一建', -> PRIMARY KEY (`id`), -> UNIQUE KEY `uniq_flag` (`uniq_flag`) USING BTREE -> ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='测试表'; Query OK, 0 row...
REPLACE ® REPLICA; added in 8.0.22 (nonreserved) REPLICAS; added in 8.0.22 (nonreserved) REPLICATE_DO_DB REPLICATE_DO_TABLE REPLICATE_IGNORE_DB REPLICATE_IGNORE_TABLE REPLICATE_REWRITE_DB REPLICATE_WILD_DO_TABLE REPLICATE_WILD_IGNORE_TABLE REPLICATION REQUIRE ® REQUIRE_ROW_FORMAT; added in...
I am trying to replace my primary key columns that contain empty string with NULL, as the primary key do not allow NULL, this will effectively not allow empty strings in my primary keys. It works great for 3 out of 4 of the primary keys, however the final one is not replacing empty ...
In this example, if the@namevariable is missing,IFNULLreplaces it with an empty string to ensure that the number of arguments matches the number of placeholders. Alternatively, you can pass all the required variables explicitly to the format string: ...
MySQL empty-string vs SQLite NULLfrom MariaDBdocumentation:If a NULL value is single-row inserted ...
• Error number: 1718; Symbol: ER_BINLOG_UNSAFE_CREATE_REPLACE_SELECT; SQLSTATE: HY000 Message: CREATE... REPLACE SELECT is unsafe because the order in which rows are retrieved by the SELECT determines which (if any) rows are replaced. This order cannot be predicted and may differ on ...
关键字是在 SQL 中具有重要意义的词。某些关键字(如SELECT、DELETE或BIGINT)是保留关键字,需要特殊处理才能用作表名和列名等标识符。这也可能适用于内置函数的名称。 允许非保留关键字作为标识符而不用引号。如果您按照第 9.2 节,“模式对象名称”中的描述引用保留字,则允许它们作为标识符: ...
split() 字符串的拆分成一个String[]数组 contains() 当且仅当此字符串包含指定的char值序列时才返回true。 查找该序列,如果其中包含有所查找的内容返回true。 concat() 将两个字符串拼接起来,相当于“+” endsWith() 判断是否以指定字符串结尾 isEmpty() 判断是否为空字符串,但不是null,而是长度为0,即 len...
-- robin.logs show create table robin.logs; -- 表结构 CREATE TABLE `logs` ( `id` int(11) unsigned NOT NULL AUTO_INCREMENT, `content` text NOT NULL, `user_id` int(11) NOT NULL, `status` enum('SUCCESS','FAILED','PROCESSING') NOT NULL, `type` varchar(20) DEFAULT '', `meta` ...