Please find below query.
select * from table tab1,
table tab2,
table tab3
where tab1.sid = tab2.sid
and tab2.referencedid = tab3.referencedid
My requirement is tab3's column value which tab3.referencedid is not then use the and condition and populate the records. Please suggest me a way how to achieve this. Based on NOT NULL condition query results should be obtained
As i understand you in this case better to use JOIN instend of using join in Where clause
SELECT *
FROM table1 t1
JOIN table2 t2 ON t1.sid = t2.sid
JOIN table3 t3 ON t2.referencedid = t3.referencedid
WHERE // here you can add your criteria if you have
The syntax for the IS NOT NULL Condition in MySQL is:
field IS NOT NULL
Related
I need to join MySQL tables.
but when I apply where clause on the second table, query return no record.
I want a query that returns all records of the 1st table and joins with 2nd table data on certain conditions and if the condition does not find records in the second table then it appends null in the result.
Please see the attached picture for detail.
enter image description here
SELECT *
FROM `Table1`
JOIN `Table2` ON `Table1`.`id1` = `Table2`.`id2`
WHERE `Table2`.`department_id` = 2;
Use a left join, and move the where criteria to the join condition:
SELECT *
FROM Table1 t1
LEFT JOIN Table2 t2 ON t1.id1 = t2.id2 AND t2.department_id = 2;
I have two interconnected tables: one stores some general result (table1), the other one details N rows for each result (table2).
Each record in table2 has a field recording the "auto_id" of the table1 row of reference (field is called "ref_id")
I intentionally deleted some records from the table1, but I left the referenced rows in table2.
How can I find all rows with invalid "ref_id"s in table2 that link to a no more existing "auto_id" in table1?
I was thinking something like
SELECT *
FROM table2
WHERE NOT EXISTS(
SELECT auto_id
FROM 'table1'
WHERE 'table2.res_id' = auto_id
)
but there-s obviously some error.
Thanks for the help!
You are using the wrong quotes. Single-quotes (apostrophes, or ASCII 39) are for literal strings. The easiest solution would be to remove the quotes:
SELECT *
FROM table2
WHERE NOT EXISTS(
SELECT auto_id
FROM table1
WHERE table2.res_id = auto_id
);
If you want to quote identifiers in MySQL, use backticks (ASCII 96).
SELECT *
FROM `table2`
WHERE NOT EXISTS(
SELECT auto_id
FROM `table1`
WHERE `table2`.`res_id` = `auto_id`
);
The cleanest way IMHO is an outer join filtering for missing rows:
SELECT t2.*
FROM table2
LEFT JOIN table1 t1 ON t1.auto_id = t2.res_id
WHERE t1.auto_id IS NULL
This works because missed left joins have all nulls in their columns and where clause conditions are applied after the join is made - the IS NULL condition means the only rows returned are those that don't have a matching row in the other table.
As well as being the most efficient (assuming an index on table1.auto_id), it also makes for a briefer query than a NOT IN (...) query.
MySQL JOIN is the best option for you.
Try this:
SELECT *
FROM table2 T2
JOIN table1 T1
ON T2.`res_id` != T1.`auto_id`
I need to build a update query. My existing code looks like this.
update table1
set data_plan=(select d.data_plan from table1 m,table2 d
where m.msidn = d.msidn and m.data_plan!=d.data_plan);
table 1 has columns msisdn and data_plan, table 2 also has same columns. I want to update the table1 data_plan column depending on some condition which I get through select query. But when I run the code I get this error.
You can't specify target table 'msisdn1' for update in FROM clause
Try it this way
update table1 m join table2 d
on m.msidn = d.msidn
and m.data_plan != d.data_plan
set m.data_plan = d.data_plan
Try this ...
UPDATE table1 SET m.data_plan=d.data_plan
FROM table1 m
INNER JOIN table2 d ON m.msidn = d.msidn and m.data_plan!=d.data_plan
Am trying to get the all rows from Tabl1 which are not available in Table2 with help of NOT IN MSQL query. But am getting timeout exception and query is not getting executed. Below is the mysql query which I am using.
SELECT * FROM identity WHERE
unique_id NOT IN (SELECT Message_Queue.index FROM Message_Queue);
Could any please tell the reason or any other way for replacement of NOT IN operation?
When you have so many records in the in() clause then you should use a join instead
SELECT t1.*
FROM table1 t1
left join table2 t2 on t2.myId = t1.myId
where t2.myId is null
Because in MySQL NOT IN is less performant, try using EXISTS
SELECT *
FROM identity a
WHERE NOT EXISTS
(
SELECT null
FROM Message_Queue b
WHERE b.index = a.unique_id
);
you should also put an index on those columns.
Is it possible in MySQL to change the JOIN of a table based on whats in a particular field of a record?
Example:
SELECT
CASE table0.status
WHEN 1 THEN table1.id
WHEN 2 THEN table2.id
END
FROM
table0, table1, table2
IF (table0.status = 1, INNER JOIN queue ON table1.id = table0.product, INNER JOIN queue ON table2.id = table0.product)
I need the joined table to be table1 if the value for 'product' in table0 = 1 or table2 if the value for 'product' in table0 is 2.
When I try the above example I only get mysql syntax errors. Ive also tried it with CASE statement instead of the IF but still not working.
I think a subselect will be a better solution than JOIN in this case. You can use a CASE statement with a SELECT inside it.