(7)ref字段说明 (8)rows字段说明 (9)filtered字段说明 (10)extra字段说明 (1)数据准备 代码语言:javascript 复制 --创建数据库CREATEDATABASEtestCHARACTERSET'utf8';--创建表CREATETABLEL1(idINTPRIMARYKEYAUTO_INCREMENT,titleVARCHAR(100));CREATETABLEL2(idINTPRIMARYKEYAUTO_INCREMENT,titleVARCHAR(100));CREATET...
-- 窗口1,开启事务 mysql> begin; Query OK, 0 rows affected (0.00 sec) -- 窗口1,查询number = 3的数据添加间隙锁 mysql> select * from test_Gaplock2 where number = 3 for update; +---+---+ | id | number | +---+---+ | 5 | 3 | +---+---+ 1 row in set (0.00 sec) ...
默认的整数位为10, 默认的小数位为0 示例: create table t1 ( id1 float(5,2) default null, id2 double(5,2) default null, id3 decimal(5,2) default null ); mysql root@localhost:test1> desc t1 +---+---+---+-
-> runoob_count INT -> ); Query OK, 0 rows affected (0.05 sec) mysql> INSERT INTO runoob_test_tbl (runoob_author, runoob_count) values ('RUNOOB', 20); mysql> INSERT INTO runoob_test
| id | select_type | table |partitions| type |possible_keys| key | key_len | ref | rows | filtered | Extra | +---+---+---+---+---+---+---+---+---+---+---+---+ | 1 | SIMPLE | student | NULL | ALL | NULL | NULL | NULL | NULL | 4 | 100.00 | Using w...
in a manner that, after sort is done, the reads of the rows are done from sorted file ONLY, without touching the table(s) involved. In spite of the reduction of the sort buffer size required, you still have to have a sort buffer large enough so that several rows can be read and wr...
错误:1409 SQLSTATE: HY000 (ER_LOAD_FROM_FIXED_SIZE_ROWS_TO_VAR) 消息:不能从具有固定大小行的文件中将值加载到变量。 错误:1410 SQLSTATE: 42000 (ER_CANT_CREATE_USER_WITH_GRANT) 消息:不允许用GRANT创建用户。 错误:1411 SQLSTATE: HY000 (ER_WRONG_VALUE_FOR_TYPE) 消息:不正确的%s值,’%s’,对...
在计算机中字符是以二进制的格式存储的,每个字符在字符编码系统中都有一个唯一的二进制代码,这个过程确保了字符在存储和传输时不会丢失或混淆。将一个字符映射成一个二进制数据的过程就称为字符编码,而将一个二进制数据映射到一个字符的过程就称为字符解码。而字符集就是一套字符和二进制数据映射关系的集合。
mysqli_set_charset(mysqli $mysql, string $charset) mysqli_query(mysqli $mysql, string $query) mysqli_insert_id(mysqli $mysql) 设置客户端字符集,若成功返回true,失败返回 false 执行数据库查询,写操作返回true,读操作返回 结果集对象,失败返回false 获取上一次插入操作产生的id mysqli_affected_rows(my...
(via release_auto_increment from WL 3146). The lock is kept from the first reservation if it is statement based replication and a multi-row INSERT statement where the number of candidate rows to insert is not known in advance (like INSERT SELECT, LOAD DATA, unlike INSERT VALUES (row1), ...