Alias a mysql table for a session? - mysql

Question

I know you can give an alias to a table for a query, like SELECT 1 FROM table AS t but is there a way to give an alias to a table for a session?
The use case is I have a "query pattern" that should apply to 3 different tables. So I would like to make only one query, using a table alias, and then tell mysql "Execute this query considering that is alias is table1, then execute the same query considering the alias is table2,..."
The use case:
INSERT INTO aliasedTable (id, value) VALUES (1,1)
The tables
CREATE TABLE table1 (id INT UNSIGNED, value TINYINT UNSIGNED)
CREATE TABLE table2 (id INT UNSIGNED, value TINYINT UNSIGNED)
CREATE TABLE table3 (id INT UNSIGNED, value TINYINT UNSIGNED)
The "supposed" syntax
ALIAS table1 AS aliasedTable;
INSERT INTO aliasedTable (id, value) VALUES (1,1)
ALIAS table2 AS aliasedTable;
INSERT INTO aliasedTable (id, value) VALUES (1,1)
ALIAS table3 AS aliasedTable;
INSERT INTO aliasedTable (id, value) VALUES (1,1)
What I thought of, is making a updatable VIEW of the table, but there is no such thing like CREATE TEMPORARY VIEW .... And using a CREATE TEMPORARY TABLE aliasedTable AS (SELECT * FROM table1) would create a table copy, instead of inserting in the original table.
Any suggestion?
Note that I have such case in a PHP code, but also in a procedure:
<?php
$query = 'INSERT INTO aliasedTable (id, value) VALUES (1,1)';
foreach (array('table1', 'table2', 'table3') AS $t) {
// Ideally, I would like to avoid string concat here and tell MySQL
// something like 'ALIAS :placeholder AS aliasedTable', ['placeholder' => $t]
$pdo->query('ALIAS ' . $table1 . ' AS aliasedTable');
$pdo->query($query);
}
or
SET #tables := '["table1","table2","table3"]';
SET #i := JSON_LENGTH(#tables) - 1;
WHILE (#i >= 0) DO
SET #table := JSON_UNQUOTE(JSON_EXTRACT(#tables, CONCAT('$[', #i, ']')));
ALIAS #table AS aliasedTable;
CALL inserting();
SET #i := #i - 1;
END WHILE;
where
CREATE PROCEDURE inserting()
BEGIN
INSERT INTO aliasedTable (id, value) VALUES (1, 1);
END$$

Answer 1

One thing that you could do is switch to a dynamic SQL statement and pass the table name as an input argument to the inserting function:
CREATE PROCEDURE inserting( IN tbl_name VARCHAR(25) )
BEGIN
SET #stmt = CONCAT('INSERT INTO ', tbl_name, ' (id, value) VALUES (1, 1)');
PREPARE stmt FROM #stmt;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
END
Depending on your call this will insert data to appropriate table. As an example:
CALL inserting('table1');
will execute following statement:
INSERT INTO table1 (id, value) VALUES (1,1);
Then from PHP you could call this procedure for each element in your array passing the current element as an argument to the function.