大约有 7,000 项符合查询结果（耗时：0.0146秒） [XML]
MySQL Conditional Insert
...his, dual is a table with one row only (found originally in Oracle, now in mysql too). The logic is that the SELECT statement generates a single row of data with the required values, but only when the values are not already found.
Alternatively, look at the MERGE statement.
...
【BLE技术内幕】BLE技术揭秘 - 创客硬件开发 - 清泛IT论坛，有思想、有深度
...个时间点把数据包发送出去，怎么保证数据的完整性，ACK如何接收，如何进行重传，以及如何对链路进行管理和控制等等。LL层只负责把数据发出去或者收回来，对数据进行怎样的解析则交给上面的GAP或者ATTHost Controller Interface，...
MySQL and GROUP_CONCAT() maximum length
I'm using GROUP_CONCAT() in a MySQL query to convert multiple rows into a single string.
However, the maximum length of the result of this function is 1024 characters.
...
How to do a regular expression replace in MySQL?
...
With MySQL 8.0+ you could use natively REGEXP_REPLACE function.
12.5.2 Regular Expressions:
REGEXP_REPLACE(expr, pat, repl[, pos[, occurrence[, match_type]]])
Replaces occurrences in the string expr that match the regular express...
Does MySQL index foreign key columns automatically?
Does MySQL index foreign key columns automatically?
9 Answers
9
...
mysql: see all open connections to a given database?
With administrative permissions im mysql, how can I see all the open connections to a specific db in my server?
8 Answers
...
Easiest way to copy a table from one database to another?
...
If you have shell access you may use mysqldump to dump the content of database1.table1 and pipe it to mysql to database2. The problem here is that table1 is still table1.
mysqldump --user=user1 --password=password1 database1 table1 \
| mysql --user=user2 --pass...
How to remove all MySQL tables from the command-line without DROP database permissions? [duplicate]
How do I drop all tables in Windows MySQL, using command prompt? The reason I want to do this is that our user has access to the database drops, but no access to re-creating the database itself, for this reason we must drop the tables manually. Is there a way to drop all the tables at once? Bear in ...
Error renaming a column in MySQL
...
The standard Mysql rename statement is:
ALTER [ONLINE | OFFLINE] [IGNORE] TABLE tbl_name
CHANGE [COLUMN] old_col_name new_col_name column_definition
[FIRST|AFTER col_name]
for this example:
ALTER TABLE xyz CHANGE manufacurerid manuf...
How do I enlarge an EER Diagram in MySQL Workbench?
I am working on a moderately complex schema in MySQL Workbench, and the single page of the EER diagram is now full up. Does anyone know how to enlarge it to two or more pages?
...