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Change One Cell's Data in mysql
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I was confused by this answer, thinking SET selected rows to change, and WHERE changed them.
– Keith
May 30 '17 at 18:50
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When to use single quotes, double quotes, and backticks in MySQL
...ng query will produce different results (or errors) depending on SQL mode:
SELECT "column" FROM table WHERE foo = "bar"
ANSI_QUOTES disabled
The query will select the string literal "column" where column foo is equal to string "bar"
ANSI_QUOTES enabled
The query will select the column column where ...
MySQL: @variable vs. variable. What's the difference?
...ialize this variable with a SET statement or inside a query:
SET @var = 1
SELECT @var2 := 2
When you develop a stored procedure in MySQL, you can pass the input parameters and declare the local variables:
DELIMITER //
CREATE PROCEDURE prc_test (var INT)
BEGIN
DECLARE var2 INT;
SET var2 =...
Memcached下一站：HandlerSocket！ - 更多技术 - 清泛网 - 专注C/C++及内核技术
...没有实际运行SQL，所以Binlog记录的是Row格式。
SQL原型：SELECT id, a, b FROM test.t WHERE id = 1 LIMIT 1
shell> telnet localhost 9999
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
P 1 test t PRIMARY id,a,b
0 1
1 = ...
how to convert a string to date in mysql?
I have a string column which acts as a date and I want to select it as a date .
5 Answers
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Delete with Join in MySQL
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Since you are selecting multiple tables, The table to delete from is no longer unambiguous. You need to select:
DELETE posts FROM posts
INNER JOIN projects ON projects.project_id = posts.project_id
WHERE projects.client_id = :client_id
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Checking for an empty field with MySQL
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I have same comment as Quassnoi's. I issue "select orig_id,hotline from normal_1952 where !(hotline > '')" and there's one record with null hotline but it doesn't match.I'm using MySQL 5.6
– Scott Chu
Apr 15 '16 at 10:16
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Maximum number of records in a MySQL database table
...g with multiple billions of entries? (which would probably just make your select statements melt down long before then)
– Kzqai
Apr 26 '10 at 19:35
2
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How to find all the tables in MySQL with specific column names in them?
... all tables with columns columnA or ColumnB in the database YourDatabase:
SELECT DISTINCT TABLE_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE COLUMN_NAME IN ('columnA','ColumnB')
AND TABLE_SCHEMA='YourDatabase';
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What is InnoDB and MyISAM in MySQL?
... INSERT statement can be executed to add rows to the end of the table with select at same time if there are no holes/deleted rows in middle of table (at time of concurrent insert).
The default isolation level og mysql InnoDB is "Read Repeatable". For MyISAM, there is no transaction. InnoDB uses row...