MySQL use a wild card in table name - mysql

Question

So I have a software that store data on those tables. I know how those tables start but there will be always a suffix to them that's a number which I have no idea to know
example of those table name is "itemid5_4423"
I know there is a table with the name itemid5 but i have no way to know the suffix number
is there a wild card something similar to this logic select * from itemid5_*;

Answer 1

Let's say you have 2 tables like this:
create table itemid5_1111 (id int, itemname varchar(100));
create table itemid5_2222 (id int, itemname varchar(100));
You insert data into them:
insert into itemid5_1111 values (1, 'first table');
insert into itemid5_2222 values (2, 'second table');
Your goal is to get output like this from all itemid5* tables.
+------+--------------+
| id | itemname |
+------+--------------+
| 1 | first table |
| 2 | second table |
+------+--------------+
You can do that by typing:
select * from itemid5_1111
union all select * from itemid5_2222;
But, that's a lot of manual typing. You can make a stored procedure to dynamically query table names starting with itemid5 and then create a SQL dynamically and execute it.
Stored procedure
delimiter $$
drop procedure if exists get_items$$
create procedure get_items()
begin
declare eof boolean default false;
declare mytable varchar(255);
declare first_run boolean default true;
declare tablenames_cursor cursor for
select table_name from information_schema.tables
where table_name like 'itemid%';
declare continue handler for not found
set eof = true;
set #my_query = '';
open tablenames_cursor;
read_loop: loop
fetch tablenames_cursor into mytable;
if eof then
leave read_loop;
end if;
if first_run then
set #my_query = concat('select * from ', mytable);
set first_run = false;
else
set #my_query = concat(#my_query, ' union all ', 'select * from ', mytable);
end if;
end loop;
close tablenames_cursor;
prepare stmt from #my_query;
execute stmt;
deallocate prepare stmt;
end$$
delimiter ;
You call this procedure like so to get your results:
call get_items();
If you created a 3rd table like so:
create table itemid5_3333 (id int, itemname varchar(100));
insert into itemid5_3333 values (3, 'third table');
And then, you called the proc, you'd get
call get_items();
+------+--------------+
| id | itemname |
+------+--------------+
| 1 | first table |
| 2 | second table |
| 3 | third table |
+------+--------------+

Answer 2

i think using the data dictionary to retrieve the result would help, run this.
select * from information_schema.tables where table_name like 'itemid5_% ';
you can choose the columns you want that this query outputs, table_name is one of them you need, like we used it in where clause.

Answer 3

SELECT
REPLACE
(
GROUP_CONCAT(
CONCAT("SELECT * FROM ", `TABLE_NAME`)
),
",",
" UNION ALL "
)
INTO #sq
FROM
information_schema.tables
WHERE
`TABLE_SCHEMA` = "test";
USE
test;
PREPARE
stmt1
FROM
#sq;
EXECUTE
stmt1;

Answer 4

DELIMITER //
CREATE PROCEDURE merge_tables(IN in_sname VARCHAR(64),IN in_tname VARCHAR(64))
READS SQL DATA
BEGIN
DECLARE sname VARCHAR(64);
DECLARE tname VARCHAR(64);
DECLARE cname VARCHAR(64);
DECLARE done INT DEFAULT FALSE;
DECLARE table_cur CURSOR FOR SELECT table_schema, table_name FROM
information_schema.TABLES WHERE table_schema = in_sname AND table_name LIKE
'table%';
DECLARE column_cur CURSOR FOR SELECT `COLUMN_NAME` FROM
`INFORMATION_SCHEMA`.`COLUMNS` where table_schema = in_sname and table_name
= in_tname;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
-- build column list (Using the column list for table listed in second
parameter in PROC Call)
SET #column = '';
OPEN column_cur;
column_cur_loop: LOOP
FETCH column_cur INTO cname;
IF done THEN
-- SET #column := CONCAT(#column, ') ');
LEAVE column_cur_loop;
END IF;
IF #column = '' THEN
SET #column := CONCAT(#column,cname);
ELSE
SET #column := CONCAT(#column,',',cname);
END IF;
END LOOP;
CLOSE column_cur;
-- Build UNION Query for all table starting with table%)
SET done = FALSE;
SET #sql = '';
OPEN table_cur;
table_list_loop: LOOP
FETCH table_cur INTO sname, tname;
IF done THEN
LEAVE table_list_loop;
END IF;
IF #sql = '' THEN
SET #sql := CONCAT('INSERT INTO MERGED_TABLE (', #column , ') SELECT
', #column , ' FROM `', sname, '`.`', tname, '`');
ELSE
SET #sql := CONCAT(#sql, ' UNION ALL SELECT ' , #column , ' FROM `',
sname, '`.`', tname, '`');
END IF;
END LOOP;
CLOSE table_cur;
PREPARE stmt FROM #sql; -- prepare and execute the dynamically
EXECUTE stmt; -- created query.
DEALLOCATE PREPARE stmt;
END //
DELIMITER ;`
call merge_tables(testdb,table1)
testdb is Schema Name where tables reside
table1 is one of the tables which needs to be merged to get column names
table% in the procedure is the prefix of the all the tables that needs to be merged.