I am a newbie at MySQL..... I am trying to left join 3 tables one contains some_id,name,count,descr and second one has id,some_id,uni_id and the last one has uni_id,price,added,etc So when i try to join these three tables it says that there's no such field named descr
What could be the best way to join these tables without modifying structure of them?
Assuming the following schema:
table1(some_id, name, count, descr), where some_id is the primary key;
table2(id, some_id, uni_id), where some_id is a foreign key to table1;
table3(uni_id, price, added), where uni_id is a foreign key to table2.
All you need to do is a LEFT OUTER JOIN between the three tables:
SELECT *
FROM table1 t1 LEFT JOIN table2 t2 ON (t1.some_id = t2.some_id)
LEFT JOIN table3 ON (t2.uni_id = t3.uni_id)
References:
Left Outer Join
Join Syntax
It would be ideal if you could post the schema for your tables. Without seeing the query, it sounds like you've made a reference to a field that you may have aliased to the wrong table.
At the most basic level, "descr" doesn't exist as you've tried to reference it, but beyond that, its hard to say without seeing the query itself.
SELECT descr
FROM table1
LEFT JOIN table2 ON table2.some_id = table1.some_id
LEFT JOIN table3 ON table3.uni_id = table2.uni_id
Should do the trick.
Related
I want to create View by selecting all data from multiple tables, but the error I got saying that I have duplicate columns
CREATE VIEW All_Data AS
SELECT *
FROM table1 tb1
INNER JOIN table 2 tb2 ON tb1.ID = tb2.ID
INNER JOIN table 3 tb3 ON tb2.ID = tb3.ID
INNER JOIN table 4 tb4 ON tb3.ID = tb4.ID
INNER JOIN table 5 tb5 ON tb4.ID = tb5.ID
INNER JOIN table 6 tb6 ON o.SpecialID = tb6.ID
INNER JOIN table 7 tb7 ON tb6.ID = tb7.ID
LEFT JOIN table 8 tb8 ON tb7.ID = tb8.ID
However, I am still having the same problem. I want to know is there a faster way to do that instead using alias selecting each column one by one.
DISTINCT won't help as its talking about duplicate columns vs duplicate rows.
Its the * that is causing the columns from all tables, with duplicate column names to be returned. You'll need to replace the * with explicit columns and alias them like below if both are needed.
SELECT p.created_date as product_created_date, order.created_date as order_created date .....
Note using a view isn't a needed pattern. Selects of exactly the right result are normally sufficient. Selects on views can suffer in performance as they are more complicated for MySQL to optimize. They are useful if you need an explicit GRANT on the them for a specific user however.
You need to provide the full list of columns that you want to be part of the view. There is no shortcut.
But yes, to ease your work, If you want the comma separated list of the column names of the table then you can use the following query for each table and put their columns in your select query. You will then just need to alias the columns which have same names.
Select listagg('pd.'|| column_name, ',')
Within group (order by column_id)
From user_tab_columns
Where table_name = 'your_table_name_in_capital';
Note that you need to replace 'pd.' for each table with the table alias in your query.
I have two tables with same primary key name "codigo",
I try to make a mysql query to combine both results on new one table.
SELECT * FROM recuperacion.inventario, recuperacion.Salidas where codigo='5ae2399f4fbd3';
this query is not work.
You need to join the tables.
SELECT *
FROM recuperacion.inventario
INNER JOIN recuperacion.Salidas USING (codigo)
WHERE codigo='5ae2399f4fbd3';
The USING clause can be used when the joining relationship is the same column name(s) in both tables. This then allows you to refer to that column without qualifying it with a table prefix.
SELECT t1.*, t2.*
-- INTO NewTableName
FROM recuperacion.inventario t1
INNER JOIN recuperacion.Salidas t2
ON t1.codigo = t2.codigo
WHERE t1.codigo='5ae2399f4fbd3'
NOTE: this will get you all columns from both tables. If you only want specific columns you need to edit the select list. Just be sure to use the aliases.
you have to use join
SELECT *
FROM recuperacion.inventario tab1
INNER JOIN recuperacion.Salidas tab2
on tab1.codigo = tab2.codigo
where tab1.codigo='5ae2399f4fbd3'
Use a JOIN syntax for the query:
SELECT *
FROM recuperacion.inventario a JOIN recuperacion.Salidas b
ON a.codigo = b.codigo
WHERE a.codigo='5ae2399f4fbd3';
I want to create a table that needs to be a combination of selected columns from three or more tables. I don't have any sample data, just added the columns for explanation.
Table 1
A|B1|C1|D1|E1|F1|G1|H1|I1|J1
Table 2
A|B2|C2|D2|E2|F2|G2
Table 3
A|B3|C3|D3|E3|F3|G3
Resultant New table must have
A|B1|E1|F1|G1|J1|C2|D2|G2|B3|D3|F3
I'm not sure if I need to use a FULL JOIN or use UNIONS.
Each of these tables contain more than 400,000 rows. Any help here on what query needs to be included would be really helpful.
You can try the below query:
select t1.A,t1.B1,t3.E1,t1.F1,t1.G1,t1.J1,t2.C2,t2.D2,t2.G2,t3.B3,t3.D3,t3.F3
from table1 t1 join table2 t2 on t1.A = t2.A
join table3 t3 join table2 t2 on t3.A = t2.A
As Palec commented correctly in the other answer, so adding a bit of explanation to the answer.
You need to use the JOINS for this problem instead of UNION. The reason why I am saying to use JOINS over UNION is UNION combines the data/result of two or more queries into a single result set which includes all the rows which exist in the queries in your UNION. But when you are using JOINs, you can retrieve data from two or more tables based on logical relationships between the tables.
Also to add that you should add an alias name to your table so that it becomes easy to retrieve the column in the select query and also while linking the table.
Join is the correct way:
select table1.A,B1,E1,F1,G1,J1,C2,D2,G2,B3,D3,F3 from table1 join table2 on table1.A = table2.A
join table3 join table2 on table3.A = table2.A
I have about 10 tables, all with varying number of columns but all contain the column 'client_id' which is the key to link all the records in each table together.
I want to grab all columns in all tables.
what would be the best way to join all 10 or so tables together on the client_id?
The reason for wanting to do this is because I want to export all tables in 1 single CSV file.
Start with a table that contains all the client ids and left join the remaining tables with the USING keyword:
SELECT *
FROM table1
LEFT JOIN table2 USING (client_id)
LEFT JOIN table3 USING (client_id)
LEFT JOIN table4 USING (client_id)
...
select *
from table1 t1,
table2 t2,
table3 t3...
where t1.user_id=t2.user_id
and t1.user_id=t3.user_id...
I have 3 tables which contain different types of data related to each other. the tables populate via an excel spreadsheet. I have:
table1 table2 table3
item_number item_number item_number
desc desc qty_sold
qty_instock vdf_cost upc
cost status
What I'm trying to do is use a join function to show all the data as they relate to each other, except the problem is that when I run
SELECT *
FROM table1 a
INNER JOIN table2 b
ON a.someColumn = b.otherColumn
INNER JOIN table3 c
ON b.anotherColumn = c.nextColumn
It just puts the tables side by side, If I run
SELECT *
FROM table1 a
INNER JOIN table2 b
USING(item_number)
It works but only joins the item number (i have no idea how to use multiple fields such as description which repeats), and for some reason I can only use the two tables when I try to add a third table (most likely being done completely wrong)
SELECT *
FROM table1 a
INNER JOIN table2 b
INNER JOIN table3 c
USING(item_number)
I just get a syntax error.
Thanks for all the help in advance
UPDATE:
I got it working
SELECT *
FROM master_list a
INNER JOIN bby_report ab USING (item_number, description)
INNER JOIN sales_report b USING (item_number)
Is there a way I can exclude the description from one of the tables and keep it from another one? Turns out the descriptions are not an exact match from one table to a another so it keeps returning zero results.
So to clarify keep description from table1 and leave out description from table2 while being able to JOIN the fields based on item_number
SELECT *
FROM master_list a
INNER JOIN bby_report ab USING (item_number, description)
INNER JOIN sales_report b USING (item_number)