2 tables table1 and table 2; requirement is to map two columns in table1 from table 2
SELECT , t2.people_names, t2.peoples_names
FROM ( table1 t1 JOIN table2 t2 ON t2.people_ids=t1.people1 )
If I add in the FROM statement and AND, in order to map column people2, I get an error.
FROM (table1 t1 JOIN table2 t2 ON t2.people_ids=t1.people1 AND
t2.people_ids=t1.people2 )
You have to join the people_names table two times.
SELECT t1.people1, tnames1.peoples_names, t1.people2, tnames2.peoples_names
FROM table1 t1 JOIN table2 tnames1 ON tnames1.people_ids = t1.people1
JOIN table2 tnames2 ON tnames2.people_ids = t1.people2
Related
one table t1 has one unique id u1
another table t2 has three unique_id u2a, u2b, u2c
How to make an inner join between two tables so that
u1 of table t1 join either u2a, u2b or u2c of table t2.
I don't think this is a best practice but try:
select t1.name,t2.country
from table1 t1
inner join table2 t2
on t1.u1=t2.u2a
union
select t1.name,t2.country
from table1 t1
inner join table2 t2
on t1.u1=t2.u2b
union
select t1.name,t2.country
from table1 t1
inner join table2 t2
on t1.u1=t2.u2c;
Demo: https://www.db-fiddle.com/f/7yUJcuMJPncBBnrExKbzYz/116
If you want the name in order you can add order by name desc; in the end of the query.
select t1.name,t2.country
from table1 t1
inner join table2 t2
on t1.u1=t2.u2a
union
select t1.name,t2.country
from table1 t1
inner join table2 t2
on t1.u1=t2.u2b
union
select t1.name,t2.country
from table1 t1
inner join table2 t2
on t1.u1=t2.u2c
order by name desc;
How to search three different tables with three different columns? The current command:
$sql="select t1.brand_name,t2.category_name from brand_data_add AS t1
LEFT JOIN category_add_data AS t2 ON t1.brand_name=t2.category_name
UNION select t1.brand_name,t2.category_name from brand_data_add AS t1
RIGHT JOIN category_add_data AS t2 ON t1.brand_name=t2.category_name";
SQL:
SELECT
*
FROM
(
SELECT
workouts.name,
workouts.description,
`user`.user_email
FROM
workouts
LEFT JOIN `user` ON
workouts.created_by = `user`.iduser
UNION
SELECT
workouts.name,
workouts.description,
`user`.user_email
FROM
workouts
RIGHT JOIN `user` ON
workouts.created_by = `user`.iduser) AS main_table
WHERE
user_email LIKE '%gmail%';
Explanation:
You should enclose your union query with bracket
Fetch the fields with SELECT clause
Use the WHERE clause to do the conditional filter in virtual table main_table (union of two table)
select t1.brand_name,t2.category_name, t3.? from brand_data_add AS t1
LEFT JOIN category_add_data AS t2 ON t1.brand_name=t2.category_name
LEFT JOIN t3 on t3 on t3.? = t?
UNION select t1.brand_name,t2.category_name, t3.? from brand_data_add AS t1
RIGHT JOIN category_add_data AS t2 ON t1.brand_name=t2.category_name"
RIGHT JOIN t3 on t3 on t3.? = t?
Say, myself having three MySQL tables as follows.
Table 1 contains table1id, value columns.
Table 2 contains table2id, value, table1id (as FK) columns.
Table 3 contains table3id, value, table1id (as FK) columns.
Then is the following relationship valid?
select * from table1 t1 inner join table2 t2 on t1.table1id = t2.table1id
Yes, It is possible.
This one is Joining for teable1 and table2
select * from test1 t1 inner join test2 t2 on t1.id = t2.id;
This one is joining all three tables,
SELECT * FROM test1 t1
INNER JOIN test2 t2 ON t1.id = t2.id
INNER JOIN test3 t3 ON t1.id = t3.id;
Output: ONLINE DEMO HERE
Try this
SELECT * FROM
table1 t1 INNER JOIN table2 t2
ON t1.table1id = t2.table2id
INNER JOIN table3 t3
ON t1.table1id = t3.table3id
You can also write it this way:
SELECT * FROM table1 t1, table2 t2, table3 t3
WHERE (t1.table1id=t2.table2id) AND (t1.table1id=t3.table3id);
** If you want to join only the first 2 tables--Use the code until the AND
*** If you want to join all the tables-- Use the entire code.
I'm trying to search a rows of table3 that have id match in a table1 OR table2 with this query
SELECT T1.*, T3.*,T2.*
FROM (
select id
from table1
where condition like '%field%') T1
inner join table3 T3
ON T3.id=T1.id
left join (
select id
from table2
where condition like '%field%') T2
ON T3.id=T2.id
If in table T1 have matches but in table2 not, the query works fine but if in table1 not have matches but have in table2 the query not show any results.
Someone can help me?
Thanks
do left join to avoid excluding rows, and add a where with the condition you need FOr readability sake,avoid right joins and jsut use proper table order
SELECT T1.*, T3.*,T2.*
FROM Table3 T3
left join (
select id
from table1
where condition like '%field%') T1
ON T3.id=T1.id
left join (
select id
from table2
where condition like '%field%') T2
ON T3.id=T2.id
where t3.id is not null or t2.id is not null
I have two tables. The first table contains ID, First_Name and Last_Name.
The 2nd table contains two foreign key fields containing different ID's of the first table.
I want to be able to run a SQL query that gets reults of the 2nd table which then grabs the First_Name of each member based on the two different foreign keys.
How would I go about doing this?
select t2.*, t1a.firstname, t1b.firstname
from table2 t2
left join table1 t1a on t2.fk1 = t1a.id
left join table1 t1b on t2.fk2 = t1b.id
Suppose the second table has fields as such
userid, supervisorid ( both referring to the Id column of the first table )
you may write join to get the value like this
SELECT t2.*, ID, firstname, lastname FROM table 2 t2
LEFT OUTER JOIN table 1 t1 ON
t2.userid = t1.id
OR t2.supervisorid = t1.id
I think correct sql would be below one using OR condition in outer join or using union
SELECT t1.id,t1.name from table1 t1, table2 t2 WHERE t1.id1 = t2.id1
UNION
SELECT t1.id,t1.name from table1 t1, table2 t2 WHERE t1.id1 = t2.id0
SELECT t1.id, t1.name from table2 t2 LEFT OUTER JOIN table1 t2 ON t1.id = t2.id or t1.id1 = t2.id0