$result = mysql_query($query) or die('Query failed: ' . mysql_error()); echo "The value of \$var1 is: $var1"; // display the value of the variable -- for debugging purposes. echo "The value of \$query is: $query"; // Display the query terms -- for debugging echo "...
### 先查看下默认读取sql文件大小 mysql> show VARIABLES like '%max_allowed_packet%'; +---+---+ | Variable_name | Value | +---+---+ | max_allowed_packet | 67108864 | -- 指mysql服务器端和客户端在一次传送数据包的过程当中最大允许的数据包大小 64M | mysqlx_max_allowed_packet | 6710...
原因:主键冲突 解决方法: mysql> set gtid_next='5d52e9bc-dca8-11e8-8f03-48df371d2499:500'; Query OK, 0 rows affected (0.00 sec) mysql> begin; Query OK, 0 rows affected (0.00 sec) mysql> commit; Query OK, 0 rows affected (0.00 sec) mysql> set gtid_next='automatic'; Query OK...
| Variable_name | Value | +———–+———–+ | query_cache_limit | 2097152 | | query_cache_min_res_unit | 4096 | | query_cache_size | 203423744 | | query_cache_type | ON | | query_cache_wlock_invalidate | OFF | +———–+———+...
User variables, even though not part of standard SQL, are great objects in MySQL. They allow to keep some “state” for the life of a session: a session can execute a statement to compute a value, store that value in a user variable, and use it in all next statements. This avoids...
-O, --set-variable=name //设置变量用法是--set-variable=var_name=var_value --sigint-ignore //忽视SIGINT符号(登录退出时Control-C的结果) -o, --one-database //忽视除了为命令行中命名的默认数据库的语句。可以帮跳过日志中的其它数据库的更新。
与查询缓冲有关的参数还有query_cache_type、query_cache_limit、query_cache_min_res_unit。query_cache_type指定是否使用查询缓冲,可以设置为0、1、2,该变量是SESSION级的变量。query_cache_limit指定单个查询能够使用的缓冲区大小,缺省为1M。query_cache_min_res_unit是在4.1版本以后引入的,它指定分配缓冲区空间的...
ERROR1229(HY000): Variable'max_connect_errors'isaGLOBALvariableandshould besetwithSETGLOBALmysql> 3.2 设置session参数: mysql>setNET_RETRY_COUNT=15; Query OK,0rowsaffected (0.00sec) mysql>showvariableslike'NET_RETRY_COUNT';+---+---+|Variable_name|Value|+---+---+|net_retry_count|15|+---...
To avoid problems with this behavior, either do not assign a value to and read the value of the same variable within a single statement, or else set the variable to0,0.0, or''to define its type before you use it. In aSELECTstatement, each select expression is evaluated only when sent...
1. If I do the following simple query, I get the correct result set SELECT AccountId, NumLicenses FROM Accounts WHERE UserName = 'my_username' AND Password = 'my_password'; But if I try to replace the hard coded string w/ a variable, it doesn't give me any errors, but also doesn...