I have a table like:
id name children
1 Roberto Michael,Dia
2 Maria John,Alex
3 Mary Alexandre,Diana
My problem is;
I want to find who has a child named Alex.
I can't use "where children = 'Alex'" in SQL because I have more than one names in same cells.
So I use "where children LIKE '%Alex%'" - that looks smart but
in the same time i get all start like Alex :( Alexandre
or i want to get dia but result is dia and diana :(
how can I get single Alex in that data type?
I hope I can explain my problem with my terrible english :D
The best solution would be to normalize your schema. You should have a separate table with one row for each child, instead of a comma-delimited list. Then you can join with this table to find parent with a specific child. See #themite's answer for an example of this.
But if you can't do that for some reason, you can use FIND_IN_SET:
WHERE FIND_IN_SET('Alex', children)
You should split the data into two tables.
the first would look like this
ID Name
1 Roberto
2 Maria
3 Mary
And the second like this
ParentId child
1 Michael
1 Dia
2 John
2 Alex
and so on.
then you could do the query you want without having to worry about like and your data is much more useable
That's why you'd want to have two tables here.
parents:
id name
1 Roberto
2 Maria
3 Mary
children:
id parentid name
1 1 Michael
2 1 Dia
3 2 John
4 2 Alex
5 3 Alexandre
6 3 Diana
And now you can query this much more effectively with a join or an exists:
SELECT *
FROM Parents
WHERE EXISTS(
SELECT *
FROM Children
WHERE parentid=Parents.id
AND Children.name='Alex'
)
I would rather make different tables for children and parents something like this.
Table for parents
parent_id name
1 Roberto
2 Maria
3 Mary
Table for children
children_id parent_id name
1 1 Michael
2 1 Dia
3 2 John
.... and so on
Related
I have a table like:
id name children
1 Roberto Michael,Dia
2 Maria John,Alex
3 Mary Alexandre,Diana
My problem is;
I want to find who has a child named Alex.
I can't use "where children = 'Alex'" in SQL because I have more than one names in same cells.
So I use "where children LIKE '%Alex%'" - that looks smart but
in the same time i get all start like Alex :( Alexandre
or i want to get dia but result is dia and diana :(
how can I get single Alex in that data type?
I hope I can explain my problem with my terrible english :D
The best solution would be to normalize your schema. You should have a separate table with one row for each child, instead of a comma-delimited list. Then you can join with this table to find parent with a specific child. See #themite's answer for an example of this.
But if you can't do that for some reason, you can use FIND_IN_SET:
WHERE FIND_IN_SET('Alex', children)
You should split the data into two tables.
the first would look like this
ID Name
1 Roberto
2 Maria
3 Mary
And the second like this
ParentId child
1 Michael
1 Dia
2 John
2 Alex
and so on.
then you could do the query you want without having to worry about like and your data is much more useable
That's why you'd want to have two tables here.
parents:
id name
1 Roberto
2 Maria
3 Mary
children:
id parentid name
1 1 Michael
2 1 Dia
3 2 John
4 2 Alex
5 3 Alexandre
6 3 Diana
And now you can query this much more effectively with a join or an exists:
SELECT *
FROM Parents
WHERE EXISTS(
SELECT *
FROM Children
WHERE parentid=Parents.id
AND Children.name='Alex'
)
I would rather make different tables for children and parents something like this.
Table for parents
parent_id name
1 Roberto
2 Maria
3 Mary
Table for children
children_id parent_id name
1 1 Michael
2 1 Dia
3 2 John
.... and so on
I have a table like:
id name children
1 Roberto Michael,Dia
2 Maria John,Alex
3 Mary Alexandre,Diana
My problem is;
I want to find who has a child named Alex.
I can't use "where children = 'Alex'" in SQL because I have more than one names in same cells.
So I use "where children LIKE '%Alex%'" - that looks smart but
in the same time i get all start like Alex :( Alexandre
or i want to get dia but result is dia and diana :(
how can I get single Alex in that data type?
I hope I can explain my problem with my terrible english :D
The best solution would be to normalize your schema. You should have a separate table with one row for each child, instead of a comma-delimited list. Then you can join with this table to find parent with a specific child. See #themite's answer for an example of this.
But if you can't do that for some reason, you can use FIND_IN_SET:
WHERE FIND_IN_SET('Alex', children)
You should split the data into two tables.
the first would look like this
ID Name
1 Roberto
2 Maria
3 Mary
And the second like this
ParentId child
1 Michael
1 Dia
2 John
2 Alex
and so on.
then you could do the query you want without having to worry about like and your data is much more useable
That's why you'd want to have two tables here.
parents:
id name
1 Roberto
2 Maria
3 Mary
children:
id parentid name
1 1 Michael
2 1 Dia
3 2 John
4 2 Alex
5 3 Alexandre
6 3 Diana
And now you can query this much more effectively with a join or an exists:
SELECT *
FROM Parents
WHERE EXISTS(
SELECT *
FROM Children
WHERE parentid=Parents.id
AND Children.name='Alex'
)
I would rather make different tables for children and parents something like this.
Table for parents
parent_id name
1 Roberto
2 Maria
3 Mary
Table for children
children_id parent_id name
1 1 Michael
2 1 Dia
3 2 John
.... and so on
I could not find an answer by searching as I am not sure what exactly it would be called what I'm searching for.
Anyways, I have multiple tables in MySQL and am trying to "fill in" some of the final product.
myTable
id assigned_to location
1 2 3
2 2 3
3 3 3
myUsers
id name
1 John
2 David
3 Sally
myLocation
id name
1 SAT
2 DEN
3 AUS
Basically the end product should pull the "myTable" data and fill into a table (which I already know how to do) the name and location of each row/column so that it states something alongm the lines of
ID Assigned To Location
1 David SAT
Instead of
ID Assigned To Location
1 2 2
This should produce the expected result:
SELECT mt.id, mu.name, ml.name
FROM mytable mt JOINT myUsers mu ON mt.assigned_to = mu.id
JOIN myLocation ml ON mt.location = ml.id
I would really appreciate your help on this:
Item_ID Buy_User Buy_Date Buy_Qty
00001 Adam 01/02/2013 1
00003 John 01/01/2013 2
00004 Peter 02/01/2013 1
00001 Nial 01/01/2013 1
Above is an example of my table. What I need is to sql query the Item_ID column, and display each Item_ID only once - but display each of the user's who have bought that product.
I need the query to be outputted in HTML/css.
For example my html page may look like:
Item 1: Adam bought 1. Nial bought 1.
Item 2: (would be hidden as no purchases).
Item 3: John bought 2.
Item 4: Peter bought 1.
I'm not quite sure how to achieve this, I've been googling around and found multiple mentions of sub selects, but i'm not sure how i'd get it to display each row?
Help?!
Many thanks.
Is this what you're looking for? It uses GROUP_CONCAT to group the rows and CONCAT to build the strings:
SELECT Item_Id, GROUP_CONCAT(CONCAT(Buy_User,' bought ',Buy_Qty) SEPARATOR ', ') ITEMS
FROM Items
GROUP BY Item_Id
Here is the SQL Fiddle.
And here are the results:
ITEM_ID ITEMS
00001 Adam bought 1, Nial bought 1
00003 John bought 2
00004 Peter bought 1
I'm using PHP/MySQL and I have to create a new table from an existing one. Here's the problematic:
Table1:
photo_id email name_to creation_date link
1 foo1#bar.com paul 2012-11-21 link1.com
2 foo2#bar.com mark 2012-11-22 link2.com
3 foo1#bar.com alex 2012-11-23 link3.com
4 foo1#bar.com saul 2012-11-25 link4.com
5 foo1#bar.com john 2012-11-26 link5.com
6 foo2#bar.com math 2012-11-27 link6.com
7 foo3#bar.com fred 2012-11-28 link7.com
In Table1 the email is not unique, it can be repeated several times. Each link is different. With this data, I have to create a new table in which the email is unique with maximum of 3 links if there's more entries of one email (if so I need the data of the 3 latest entries).
So, in this case, Table2 would be like:
email link1 creation_date1 name_to1 link2 creation_date2 name_to2 link3 creation_date3 name_to3
foo1#bar.com link5.com 2012-11-26 john link4.com 2012-11-25 saul link3.com 2012-11-23 alex
foo2#bar.com link6.com 2012-11-27 math link2.com 2012-11-22 mark
foo3#bar.com link7.com 2012-11-28 fred
I know the GROUP_CONCAT feature but it's not really what I need here since the links would all be in the same column. Is it better to make a SELECT * FROM table1 and process the result into PHP arrays and after that create Table2 or a unique MySQL query would do the trick? Or create multiple MySQL tables?
Table1 is over 10 millions rows.
Any advice would be appreciate.
Thanks.
1) select all unique emails.
2) For each email, take the first 3 rows with that email ordered by creation_date descending.
3) Use that data to insert into new table.
Whatchu think?