MySQL Stored Procedure to loop through 2 tables, select values, and store in 3rd
I have 3 tables users, memos, and memos_read.
users:
+---+----------+
|ID | NAME |
+---+----------+
| 1 | Mike |
| 4 | Susan |
| 5 | Peter |
| 6 | Mary |
+---+----------+
memos:
+---+----------+
|ID | CONTENT |
+---+----------+
| 15| Hello |
| 16| World |
| 17| Foo |
| 23| Bar |
+---+----------+
I want to create a stored procedure with a nested loop to create a "read map" for memos that have been read, creating something like:
memos_read:
+---------+----------+
| MEMO_ID | USER_ID |
+---------+----------+
| 15 | 1 |
| 15 | 4 |
| 15 | 5 |
| 15 | 6 |
| 16 | 1 |
| 16 | 4 |
| 16 | 5 |
| 16 | 6 |
| 17 | 1 |
| 17 | 4 |
| 17 | 5 |
| 17 | 6 |
| 23 | 1 |
| 23 | 4 |
| 23 | 5 |
| 23 | 6 |
+---------+----------+
Is this possible? Thank you in advanced!
mysql stored-procedures
asked Nov 23 '18 at 6:21
Mike FengMike Feng
3791313
add a comment |
I have 3 tables users, memos, and memos_read.
users:
+---+----------+
|ID | NAME |
+---+----------+
| 1 | Mike |
| 4 | Susan |
| 5 | Peter |
| 6 | Mary |
+---+----------+
memos:
+---+----------+
|ID | CONTENT |
+---+----------+
| 15| Hello |
| 16| World |
| 17| Foo |
| 23| Bar |
+---+----------+
I want to create a stored procedure with a nested loop to create a "read map" for memos that have been read, creating something like:
memos_read:
+---------+----------+
| MEMO_ID | USER_ID |
+---------+----------+
| 15 | 1 |
| 15 | 4 |
| 15 | 5 |
| 15 | 6 |
| 16 | 1 |
| 16 | 4 |
| 16 | 5 |
| 16 | 6 |
| 17 | 1 |
| 17 | 4 |
| 17 | 5 |
| 17 | 6 |
| 23 | 1 |
| 23 | 4 |
| 23 | 5 |
| 23 | 6 |
+---------+----------+
Is this possible? Thank you in advanced!
mysql stored-procedures
asked Nov 23 '18 at 6:21
Mike FengMike Feng
3791313
1
That's just a cross join no sp required.
– P.Salmon
Nov 23 '18 at 6:36
add a comment |
I have 3 tables users, memos, and memos_read.
users:
+---+----------+
|ID | NAME |
+---+----------+
| 1 | Mike |
| 4 | Susan |
| 5 | Peter |
| 6 | Mary |
+---+----------+
memos:
+---+----------+
|ID | CONTENT |
+---+----------+
| 15| Hello |
| 16| World |
| 17| Foo |
| 23| Bar |
+---+----------+
I want to create a stored procedure with a nested loop to create a "read map" for memos that have been read, creating something like:
memos_read:
+---------+----------+
| MEMO_ID | USER_ID |
+---------+----------+
| 15 | 1 |
| 15 | 4 |
| 15 | 5 |
| 15 | 6 |
| 16 | 1 |
| 16 | 4 |
| 16 | 5 |
| 16 | 6 |
| 17 | 1 |
| 17 | 4 |
| 17 | 5 |
| 17 | 6 |
| 23 | 1 |
| 23 | 4 |
| 23 | 5 |
| 23 | 6 |
+---------+----------+
Is this possible? Thank you in advanced!
mysql stored-procedures
asked Nov 23 '18 at 6:21
Mike FengMike Feng
3791313
I have 3 tables users, memos, and memos_read.
users:
+---+----------+
|ID | NAME |
+---+----------+
| 1 | Mike |
| 4 | Susan |
| 5 | Peter |
| 6 | Mary |
+---+----------+
memos:
+---+----------+
|ID | CONTENT |
+---+----------+
| 15| Hello |
| 16| World |
| 17| Foo |
| 23| Bar |
+---+----------+
I want to create a stored procedure with a nested loop to create a "read map" for memos that have been read, creating something like:
memos_read:
+---------+----------+
| MEMO_ID | USER_ID |
+---------+----------+
| 15 | 1 |
| 15 | 4 |
| 15 | 5 |
| 15 | 6 |
| 16 | 1 |
| 16 | 4 |
| 16 | 5 |
| 16 | 6 |
| 17 | 1 |
| 17 | 4 |
| 17 | 5 |
| 17 | 6 |
| 23 | 1 |
| 23 | 4 |
| 23 | 5 |
| 23 | 6 |
+---------+----------+
Is this possible? Thank you in advanced!
mysql stored-procedures
mysql stored-procedures
asked Nov 23 '18 at 6:21
Mike FengMike Feng
3791313
asked Nov 23 '18 at 6:21
Mike FengMike Feng
3791313
asked Nov 23 '18 at 6:21
Mike FengMike Feng
3791313
asked Nov 23 '18 at 6:21
Mike FengMike Feng
3791313
asked Nov 23 '18 at 6:21
Mike FengMike Feng
3791313
3791313
1
That's just a cross join no sp required.
– P.Salmon
Nov 23 '18 at 6:36
add a comment |
1
That's just a cross join no sp required.
– P.Salmon
Nov 23 '18 at 6:36
1
1
That's just a cross join no sp required.
– P.Salmon
Nov 23 '18 at 6:36
That's just a cross join no sp required.
– P.Salmon
Nov 23 '18 at 6:36
add a comment |
2 Answers
2
active
oldest
votes
@Nick's answer should work for you; however if you are not interested in creating a new table, and rather use the "read map" dynamically inside a query; you can utilize a Derived Table.
General query structure would be something as follows:
SELECT
read_map.MEMO_ID,
read_map.USER_ID,
...
FROM
(
SELECT
m.ID AS MEMO_ID,
u.ID AS USER_ID
FROM users AS u
CROSS JOIN memos AS m
) AS read_map
... -- here you can join with other tables as required
WHERE ...
answered Nov 23 '18 at 7:25
Madhur BhaiyaMadhur Bhaiya
19.6k62236
add a comment |
You can use CREATE TABLE ... SELECT syntax to create the memos_read table:
CREATE TABLE memos_read AS
SELECT m.ID AS MEMO_ID, u.ID AS USER_ID
FROM memos m
CROSS JOIN users u
Output is as you requested. Demo on dbfiddle
answered Nov 23 '18 at 6:47
NickNick
27.4k111941
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
@Nick's answer should work for you; however if you are not interested in creating a new table, and rather use the "read map" dynamically inside a query; you can utilize a Derived Table.
General query structure would be something as follows:
SELECT
read_map.MEMO_ID,
read_map.USER_ID,
...
FROM
(
SELECT
m.ID AS MEMO_ID,
u.ID AS USER_ID
FROM users AS u
CROSS JOIN memos AS m
) AS read_map
... -- here you can join with other tables as required
WHERE ...
answered Nov 23 '18 at 7:25
Madhur BhaiyaMadhur Bhaiya
19.6k62236
add a comment |
@Nick's answer should work for you; however if you are not interested in creating a new table, and rather use the "read map" dynamically inside a query; you can utilize a Derived Table.
General query structure would be something as follows:
SELECT
read_map.MEMO_ID,
read_map.USER_ID,
...
FROM
(
SELECT
m.ID AS MEMO_ID,
u.ID AS USER_ID
FROM users AS u
CROSS JOIN memos AS m
) AS read_map
... -- here you can join with other tables as required
WHERE ...
answered Nov 23 '18 at 7:25
Madhur BhaiyaMadhur Bhaiya
19.6k62236
add a comment |
@Nick's answer should work for you; however if you are not interested in creating a new table, and rather use the "read map" dynamically inside a query; you can utilize a Derived Table.
General query structure would be something as follows:
SELECT
read_map.MEMO_ID,
read_map.USER_ID,
...
FROM
(
SELECT
m.ID AS MEMO_ID,
u.ID AS USER_ID
FROM users AS u
CROSS JOIN memos AS m
) AS read_map
... -- here you can join with other tables as required
WHERE ...
answered Nov 23 '18 at 7:25
Madhur BhaiyaMadhur Bhaiya
19.6k62236
@Nick's answer should work for you; however if you are not interested in creating a new table, and rather use the "read map" dynamically inside a query; you can utilize a Derived Table.
General query structure would be something as follows:
SELECT
read_map.MEMO_ID,
read_map.USER_ID,
...
FROM
(
SELECT
m.ID AS MEMO_ID,
u.ID AS USER_ID
FROM users AS u
CROSS JOIN memos AS m
) AS read_map
... -- here you can join with other tables as required
WHERE ...
answered Nov 23 '18 at 7:25
Madhur BhaiyaMadhur Bhaiya
19.6k62236
answered Nov 23 '18 at 7:25
Madhur BhaiyaMadhur Bhaiya
19.6k62236
answered Nov 23 '18 at 7:25
Madhur BhaiyaMadhur Bhaiya
19.6k62236
answered Nov 23 '18 at 7:25
Madhur BhaiyaMadhur Bhaiya
19.6k62236
19.6k62236
add a comment |
add a comment |
You can use CREATE TABLE ... SELECT syntax to create the memos_read table:
CREATE TABLE memos_read AS
SELECT m.ID AS MEMO_ID, u.ID AS USER_ID
FROM memos m
CROSS JOIN users u
Output is as you requested. Demo on dbfiddle
answered Nov 23 '18 at 6:47
NickNick
27.4k111941
add a comment |
You can use CREATE TABLE ... SELECT syntax to create the memos_read table:
CREATE TABLE memos_read AS
SELECT m.ID AS MEMO_ID, u.ID AS USER_ID
FROM memos m
CROSS JOIN users u
Output is as you requested. Demo on dbfiddle
answered Nov 23 '18 at 6:47
NickNick
27.4k111941
add a comment |
You can use CREATE TABLE ... SELECT syntax to create the memos_read table:
CREATE TABLE memos_read AS
SELECT m.ID AS MEMO_ID, u.ID AS USER_ID
FROM memos m
CROSS JOIN users u
Output is as you requested. Demo on dbfiddle
answered Nov 23 '18 at 6:47
NickNick
27.4k111941
You can use CREATE TABLE ... SELECT syntax to create the memos_read table:
CREATE TABLE memos_read AS
SELECT m.ID AS MEMO_ID, u.ID AS USER_ID
FROM memos m
CROSS JOIN users u
Output is as you requested. Demo on dbfiddle
answered Nov 23 '18 at 6:47
NickNick
27.4k111941
answered Nov 23 '18 at 6:47
NickNick
27.4k111941
answered Nov 23 '18 at 6:47
NickNick
27.4k111941
answered Nov 23 '18 at 6:47
NickNick
27.4k111941
27.4k111941
add a comment |
add a comment |
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1
That's just a cross join no sp required.
– P.Salmon
Nov 23 '18 at 6:36