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MySQL Insert into multiple tables? (Database normalization?)
... 2 and 3:
Will stock the LAST_INSERT_ID() in
a MySQL variable:
INSERT ...
SELECT LAST_INSERT_ID() INTO @mysql_variable_here;
INSERT INTO table2 (@mysql_variable_here, ...);
INSERT INTO table3 (@mysql_variable_here, ...);
Will stock the LAST_INSERT_ID() in a
php variable (or any language that
can c...
Row count with PDO
...
$sql = "SELECT count(*) FROM `table` WHERE foo = ?";
$result = $con->prepare($sql);
$result->execute([$bar]);
$number_of_rows = $result->fetchColumn();
Not the most elegant way to do it, plus it involves an extra query...
Simple way to calculate median with MySQL
...
In MariaDB / MySQL:
SELECT AVG(dd.val) as median_val
FROM (
SELECT d.val, @rownum:=@rownum+1 as `row_number`, @total_rows:=@rownum
FROM data d, (SELECT @rownum:=0) r
WHERE d.val is NOT NULL
-- put some where clause here
ORDER BY d.val
) ...
MySQL Insert Where query
...INSERT INTO Users(weight, desiredWeight)
VALUES (160,145)
INSERT using a SELECT statement
INSERT INTO Users(weight, desiredWeight)
SELECT weight, desiredWeight
FROM AnotherTable
WHERE id = 1
share
|
...
Is SQL syntax case sensitive?
...
The SQL Keywords are case-insensitive (SELECT, FROM, WHERE, etc), but are often written in all caps. However in some setups table and column names are case-sensitive. MySQL has a configuration option to enable/disable it. Usually case-sensitive table and column na...
MySQL Conditional Insert
...
If your DBMS does not impose limitations on which table you select from when you execute an insert, try:
INSERT INTO x_table(instance, user, item)
SELECT 919191, 123, 456
FROM dual
WHERE NOT EXISTS (SELECT * FROM x_table
WHERE user = ...
How do you debug MySQL stored procedures?
...E debug_msg(enabled INTEGER, msg VARCHAR(255))
BEGIN
IF enabled THEN
select concat('** ', msg) AS '** DEBUG:';
END IF;
END $$
CREATE PROCEDURE test_procedure(arg1 INTEGER, arg2 INTEGER)
BEGIN
SET @enabled = TRUE;
call debug_msg(@enabled, 'my first debug message');
call debug_msg(@ena...
mongo group query how to keep fields
...t suggestions]
I came here looking for an answer but wasn't happy with the selected answer (especially given it's age). I found this answer that is a better solution (adapted):
db.test.aggregate({
$group: {
_id: '$name',
person: { "$first": "$$ROOT" },
count: { $sum: 1 }
},
{
"$r...
Query to count the number of tables I have in MySQL
...
SELECT COUNT(*) FROM information_schema.tables WHERE table_schema = 'dbName';
Source
This is mine:
USE databasename;
SHOW TABLES;
SELECT FOUND_ROWS();
...
How can I tell when a MySQL table was last updated?
...e information_schema database to tell you when another table was updated:
SELECT UPDATE_TIME
FROM information_schema.tables
WHERE TABLE_SCHEMA = 'dbname'
AND TABLE_NAME = 'tabname'
This does of course mean opening a connection to the database.
An alternative option would be to "touch" a ...