Using if condition to display in mysql - mysql

I'm trying to display manager_id using the user_id and role_id as inputs in MySQL. This is what I've tried:
SELECT cbm_user.user_id as user_id
IF (cbm_roles.role_id = 3 THEN SELECT cbm_user.manager_id as manager_id, cbm_user.user_id as user_id, cbm_user_role.role_id as role_id from cbm_user left outer join cbm_user_role on cbm_user.user_id = cbm_user_role.user_id, left outer join cbm_roles on cbm_user_role.role_id = cbm_roles.role_id where role_id = 3)
END if;
But I get
#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'IF (cbm_roles.role_id = 3 THEN SELECT cbm_user.manager_id as manager_id, cbm_use' at line 2
error. What should I do? I also want to add two more conditions. How can I do that?


You are using IF in wrong way.
You are using join in wrong way means "," join as well left join together.
You can use your query below 2 types-
USE OF IF
SELECT cbm_user.user_id AS user_id
IF (cbm_roles.role_id = 3,cbm_user.manager_id,NULL) AS manager_id,
cbm_user.user_id AS user_id, cbm_user_role.role_id AS role_id
FROM cbm_user
LEFT JOIN cbm_user_role ON cbm_user.user_id = cbm_user_role.user_id
LEFT JOIN cbm_roles ON cbm_user_role.role_id = cbm_roles.role_id
WHERE role_id = 3;
use of case
SELECT cbm_user.user_id AS user_id
CASE WHEN cbm_roles.role_id = 3 THEN cbm_user.manager_id END AS manager_id,
cbm_user.user_id AS user_id, cbm_user_role.role_id AS role_id
FROM cbm_user
LEFT JOIN cbm_user_role ON cbm_user.user_id = cbm_user_role.user_id
LEFT JOIN cbm_roles ON cbm_user_role.role_id = cbm_roles.role_id
WHERE role_id = 3;


There are several syntax errors in your statement:
missing comma between fields
incorrect use of if() function
extra comma in join expression
To sum up: you cannot use an if() function to decide what tables to join. I fixed the syntax errors below, but I do not think that this is the query you want.
SELECT cbm_user.user_id as user_id,
IF(cbm_roles.role_id = 3, cbm_user.manager_id, null) as manager_id,
cbm_user_role.role_id as role_id
from cbm_user
left outer join cbm_user_role on cbm_user.user_id = cbm_user_role.user_id
left outer join cbm_roles on cbm_user_role.role_id = cbm_roles.role_id
where cbm_user_role.role_id = 3

Related

How to use VIEW in WHERE clause (MySQL)?

I want to use data of view in WHERE clause. But getting an error:
create view post_with_answers AS
SELECT DISTINCT postid
FROM (SELECT postid FROM `qa_posts` WHERE `type` = 'Q') AS q1
INNER JOIN (SELECT parentid FROM `qa_posts` WHERE `type` = 'A') AS q2 ON q1.postid = q2.parentid
select count(*)
from qa_posts
where parentid not in post_with_answers
On the last row I am getting this error:
SQL Error [1064] [42000]: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'post_with_answers' at line 3
How to fix that?

Just like you would use a table:
select count(*)
from qa_posts
where parentid not in (select pwa.postid from post_with_answers pwa);
I would caution you from using not in with a subquery. No rows are returned if even one value from the subquery is NULL. For this reason, I recommend NOT EXISTS:
select count(*)
from qa_posts p
where not exists (select 1
from post_with_answers pwa
where p.parentid = pwa.postid
);
In addition, your view definition is a bit over complicated. You don't need subqueries:
create view post_with_answers AS
SELECT DISTINCT pq.postid
FROM qa_posts pq JOIN
qa_posts pa
ON pq.postid = pa.parentid
WHERE pq.type = 'Q' AND pa.type = 'A';
Then, the DISTINCT just adds overhead, so EXISTS is better:
create view post_with_answers AS
SELECT DISTINCT pq.postid
FROM qa_posts pq
WHERE EXISTS (SELECT 1
FROM qa_posts pa
WHERE pq.postid = pa.parentid AND
pa.type = 'A'
)
WHERE pq.type = 'Q';

How to fix join error in mysql update query

I had an error in mysql as picture. please help me
sql code is following:
UPDATE
tbl_users AS Users
SET
Users.money_current = Users.money_current +
CASE
WHEN TempTbl.money_info IS NULL
THEN 0
ELSE TempTbl.money_info
END
LEFT JOIN
(SELECT
userId,
SUM(bet_money * bet_rate) AS money_info
FROM
tbl_betting
WHERE ROUND = 'xxx'
AND is_win = 1
GROUP BY userId) AS TempTbl
ON Users.userId = TempTbl.userId
FROM tbl_users AS Users;

This is the correct syntax:
UPDATE tbl_users AS Users
LEFT JOIN (
SELECT userId, SUM(bet_money * bet_rate) AS money_info
FROM tbl_betting WHERE ROUND = '965802' AND is_win = 1
GROUP BY userId
) AS TempTbl ON Users.userId = TempTbl.userId
SET Users.money_current = Users.money_current + COALESCE(TempTbl.money_info, 0)
I also changed that CASE expression with COALESCE().
But I think an INNER JOIN would also work in your case, since the unmatched rows of the LEFT JOIN that you use do not change the value of money_current.

SQL Join gives wrong results (creates duplicates)

I have a problem with my SQL join query. I have looked up other suggested answers and tried to apply it to my query, but it doesn't seem to be working.
I have this query:
SELECT SUM(p.quantity)
FROM stocktake_scans p
LEFT JOIN (
SELECT stocktake_area_id
FROM stocktake_areas
WHERE stocktake_id =8592 AND area_checked = 1
)d ON d.stocktake_area_id = p.stocktake_area_id
LEFT JOIN (
SELECT user_id
FROM stocktake_scan_edit
WHERE user_id =46521
)e ON e.user_id = p.stocktake_staff_id
WHERE p.stocktake_staff_id = 46521
And it gives me a result of 42, while I should get only 6. What is missing from the query?

I think you may have extra records with the same ID in your joined table that is where you are getting multiple rows returned from which is then calculating wrong in your sum, please try the below.
SELECT SUM(p.quantity) FROM stocktake_scans p LEFT JOIN ( SELECT distinct stocktake_area_id FROM stocktake_areas WHERE stocktake_id =8592 AND area_checked = 1 )d ON d.stocktake_area_id = p.stocktake_area_id LEFT JOIN ( SELECT distinct user_id FROM stocktake_scan_edit WHERE user_id =46521 )e ON e.user_id = p.stocktake_staff_id WHERE p.stocktake_staff_id = 46521

use subquery in inner join mysql

This is my query
SELECT CONCAT(`SM_Title`,' ',`SM_Full_Name`) AS NAME,
`RG_Date`,
`RG_Reg_No`,
`RG_Stu_ID`,
`SM_Tell_Mobile`,
`SM_Tel_Residance`,
`RG_Reg_Type`,
Default_Batch,
`RG_Status`,
`RG_Final_Fee`,
`RG_Total_Paid`,
(`RG_Final_Fee`-`RG_Total_Paid`) AS TOTALDUE,
SUM(`SI_Ins_Amount` - `SI_Paid_Amount`) AS AS_AT_APRIAL_END
INNER JOIN
(SELECT `SI_Ins_Amount`,
`SI_Reg_No`
FROM
`student_installments`
GROUP BY MONTHNAME(`SI_Due_Date`)) Z ON
Z.`SI_Reg_No` = `registrations`.`RG_Reg_No`
FROM `registrations`
LEFT JOIN `student_master` ON `student_master`.`SM_ID` = `registrations`.`RG_Stu_ID`
LEFT JOIN `student_installments` ON `student_installments`.`SI_Reg_No` = `registrations`.`RG_Reg_No`
WHERE (`RG_Reg_Type` LIKE '%HND%' OR `RG_Reg_Type` LIKE '%LMU%' )
AND `SI_Due_Date` <= '2014-04-30' GROUP BY `SI_Reg_No`
It gave me an error near
1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'Z LIMIT 0, 25' at line 1

SELECT
CONCAT(SM_Title,' ',SM_Full_Name) AS NAME,
RG_Date,
RG_Reg_No,
RG_Stu_ID,
SM_Tell_Mobile,
SM_Tel_Residance,
RG_Reg_Type,
Default_Batch,
RG_Status,
RG_Final_Fee,
RG_Total_Paid,
(RG_Final_Fee-RG_Total_Paid) AS TOTALDUE,
SUM(SI_Ins_Amount - SI_Paid_Amount) AS AS_AT_APRIAL_END
FROM registrations
INNER JOIN
(SELECT SI_Ins_Amount,SI_Reg_No
FROM student_installments
GROUP BY MONTHNAME(SI_Due_Date)) Z ON Z.SI_Reg_No = registrations.RG_Reg_No
LEFT JOIN student_master ON student_master.SM_ID = registrations.RG_Stu_ID
LEFT JOIN student_installments ON student_installments.SI_Reg_No = registrations.RG_Reg_No
WHERE (RG_Reg_Type LIKE '%HND%' OR RG_Reg_Type LIKE '%LMU%' )
AND SI_Due_Date <= '2014-04-30'
GROUP BY SI_Reg_No

I notice you have fogotten the left table or subselect that you want to join to the (SELECT SI_INs .....) and previous this I could see there is no from clause before join.
I hope this helps you
Regards

You are using from clause in wrong position it should be just after selection of your columns, you can use below query:
SELECT
CONCAT(SM_Title,' ',SM_Full_Name) AS NAME ,RG_Date,RG_Reg_No,RG_Stu_ID,SM_Tell_Mobile,SM_Tel_Residance,RG_Reg_Type,Default_Batch,RG_Status,RG_Final_Fee,RG_Total_Paid,(RG_Final_Fee-RG_Total_Paid) AS TOTALDUE, SUM(SI_Ins_Amount - SI_Paid_Amount) AS AS_AT_APRIAL_END
FROM registrations AS reg
JOIN
(SELECT
SI_Ins_Amount,SI_Reg_No
FROM student_installments
GROUP BY MONTHNAME(SI_Due_Date)) AS Z
ON Z.SI_Reg_No = reg.RG_Reg_No
LEFT JOIN student_master AS sm
ON sm.SM_ID = reg.RG_Stu_ID
LEFT JOIN student_installments AS si
ON si.SI_Reg_No = reg.RG_Reg_No
WHERE (RG_Reg_Type LIKE '%HND%' OR RG_Reg_Type LIKE '%LMU%' ) AND SI_Due_Date <= '2014-04-30'
GROUP BY SI_Reg_No;

In the part below, from keyword should go before the inner join:
FROM registrations
INNER JOIN
(SELECT SI_Ins_Amount,
SI_Reg_No
FROM student_installments
GROUP BY MONTHNAME(SI_Due_Date)
) Z
ON Z.SI_Reg_No = registrations.RG_Reg_No

Mysql query, select 2 databases with 4 tables + nested SELECT?

This is my current query:
$sel = "SELECT
db1t1.userid, db1t1.customer_id, db2t1.customers_id, db2t1.orders_id, db2t2.products_price
FROM
database1.table1 db1t1
LEFT JOIN database2.table1 db2t1 ON
db1t1.customer_id = db2t1.customers_id
LEFT JOIN database2.table2 db2t2 ON
db2t1.orders_id = db2t2.orders_id
WHERE db1t1.userid IN(
SELECT
l.userid, l.username, r.username, r.cus_id
FROM
database1.table3 l
LEFT JOIN database2.table4 r ON
l.username = r.username
WHERE r.cus_id = '1234'
)";
Error message:
Operand should contain 1 column(s)

The error occurred because that you returned a result with multiple columns to an IN clause.
Try this:
SELECT
`db1t1`.`userid`, `db1t1`.`customer_id`, `db2t1`.`customers_id`,
`db2t1`.`orders_id`, `db2t2`.`products_price`
FROM `database1`.`table1` AS `db1t1`
LEFT JOIN `database2`.`table1` AS `db2t1`
USING (`customers_id`)
LEFT JOIN `database2`.`table2` AS `db2t2`
USING (`orders_id`)
WHERE `db1t1`.`userid` IN (
SELECT `l`.`userid`
FROM `database1`.`table3` AS `l`
LEFT JOIN `database2`.`table4` AS `r`
USING (`username`)
WHERE `r`.`cus_id` = 1234
)
What are you trying to achieve ? Maybe we can find a better solution.
Also, I think that you should do an INNER JOIN instead of a LEFT JOIN in the subquery.