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Using DISTINCT and COUNT together in a MySQL Query
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use
SELECT COUNT(DISTINCT productId) from table_name WHERE keyword='$keyword'
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How do I find which transaction is causing a “Waiting for table metadata lock” state?
...about all the locks transactions are waiting for:
USE INFORMATION_SCHEMA;
SELECT * FROM INNODB_LOCK_WAITS;
A list of blocking transactions:
SELECT *
FROM INNODB_LOCKS
WHERE LOCK_TRX_ID IN (SELECT BLOCKING_TRX_ID FROM INNODB_LOCK_WAITS);
OR
SELECT INNODB_LOCKS.*
FROM INNODB_LOCKS
JOIN INNOD...
Delete all records in a table of MYSQL in phpMyAdmin
...ampserver 2.2. When I want to delete all records of a table in phpMyAdmin (select all) it deletes only one record not all records. Why it does not delete all records?
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How to get database structure in MySQL via query
...CHEMA.TABLES table. It contains metadata about all your tables.
Example:
SELECT * FROM `INFORMATION_SCHEMA`.`TABLES`
WHERE TABLE_NAME LIKE 'table1'
The advantage of this over other methods is that you can easily use queries like the one above as subqueries in your other queries.
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Does MySQL included with MAMP not include a config file?
I can't seem to find the my.cnf or other config file for the MySQL that comes with MAMP . Does it not include one?
6 Answe...
ERROR: Error 1005: Can't create table (errno: 121)
...y used somewhere else
To check constraints use the following SQL query:
SELECT
constraint_name,
table_name
FROM
information_schema.table_constraints
WHERE
constraint_type = 'FOREIGN KEY'
AND table_schema = DATABASE()
ORDER BY
constraint_name;
Look for more information there,...
selecting unique values from a column
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Use the DISTINCT operator in MySQL:
SELECT DISTINCT(Date) AS Date FROM buy ORDER BY Date DESC;
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Are nested transactions allowed in MySQL?
...Y) ENGINE=InnoDB;
START TRANSACTION;
INSERT
INTO t_test
VALUES (1);
SELECT *
FROM t_test;
id
---
1
SAVEPOINT tran2;
INSERT
INTO t_test
VALUES (2);
SELECT *
FROM t_test;
id
---
1
2
ROLLBACK TO tran2;
SELECT *
FROM t_test;
id
---
1
ROLLBACK;
SELECT *
FROM ...
How can I suppress column header output for a single SQL statement?
...in batch (using the mysql command-line binary). I want one of my several SELECT statements to not print the column headers, just the selected records. Is this possible?
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How to solve “Fatal error: Class 'MySQLi' not found”?
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Sounds like you just need to install MySQLi.
If you think you've done that and still have a problem, please post your operating system and anything else that might help diagnose it further.
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