We recently found the re-declaration issue in Mysql. If the query or procedure is called repeatedly in loop it retained last values.
SET #ToolType = 'test-Tool1';
SET #ToolType = (select Tool_type from IBP__Tool_type aa inner join IBP__xTool_set bb on aa.Tool_type_id=-1) ;
select #ToolType;
SET #ToolType = 'test-Tool1';
select #ToolType:=Tool_type from IBP__Tool_type aa inner join IBP__xTool_set bb on aa.Tool_type_id=-1;
select #ToolType; -- = OR :=
SET #ToolType = 'test-Tool2';
select Tool_type into #ToolType from IBP__Tool_type aa inner join IBP__xTool_set bb on aa.Tool_type_id=-1;
select #ToolType;
Above code will have Results : (when -1 is not present in tables so the output should be null in all cases)
null
test-tool1
test-tool2
what is the best way to resolve This Issue.
assign the variable to null before using it each time in query. User Session issues will always store the variable value in Mysql server and cause these issues.
SET #ToolType = null;
I am trying to understand how to UPDATE multiple rows with different values and I just don't get it. The solution is everywhere but to me it looks difficult to understand.
For instance, three updates into 1 query:
UPDATE table_users
SET cod_user = '622057'
, date = '12082014'
WHERE user_rol = 'student'
AND cod_office = '17389551';
UPDATE table_users
SET cod_user = '2913659'
, date = '12082014'
WHERE user_rol = 'assistant'
AND cod_office = '17389551';
UPDATE table_users
SET cod_user = '6160230'
, date = '12082014'
WHERE user_rol = 'admin'
AND cod_office = '17389551';
I read an example, but I really don't understand how to make the query. i.e:
UPDATE table_to_update
SET cod_user= IF(cod_office = '17389551','622057','2913659','6160230')
,date = IF(cod_office = '17389551','12082014')
WHERE ?? IN (??) ;
I'm not entirely clear how to do the query if there are multiple condition in the WHERE and in the IF condition..any ideas?
You can do it this way:
UPDATE table_users
SET cod_user = (case when user_role = 'student' then '622057'
when user_role = 'assistant' then '2913659'
when user_role = 'admin' then '6160230'
end),
date = '12082014'
WHERE user_role in ('student', 'assistant', 'admin') AND
cod_office = '17389551';
I don't understand your date format. Dates should be stored in the database using native date and time types.
MySQL allows a more readable way to combine multiple updates into a single query. This seems to better fit the scenario you describe, is much easier to read, and avoids those difficult-to-untangle multiple conditions.
INSERT INTO table_users (cod_user, date, user_rol, cod_office)
VALUES
('622057', '12082014', 'student', '17389551'),
('2913659', '12082014', 'assistant','17389551'),
('6160230', '12082014', 'admin', '17389551')
ON DUPLICATE KEY UPDATE
cod_user=VALUES(cod_user), date=VALUES(date)
This assumes that the user_rol, cod_office combination is a primary key. If only one of these is the primary key, then add the other field to the UPDATE list.
If neither of them is a primary key (that seems unlikely) then this approach will always create new records - probably not what is wanted.
However, this approach makes prepared statements easier to build and more concise.
UPDATE table_name
SET cod_user =
CASE
WHEN user_rol = 'student' THEN '622057'
WHEN user_rol = 'assistant' THEN '2913659'
WHEN user_rol = 'admin' THEN '6160230'
END, date = '12082014'
WHERE user_rol IN ('student','assistant','admin')
AND cod_office = '17389551';
You can use a CASE statement to handle multiple if/then scenarios:
UPDATE table_to_update
SET cod_user= CASE WHEN user_rol = 'student' THEN '622057'
WHEN user_rol = 'assistant' THEN '2913659'
WHEN user_rol = 'admin' THEN '6160230'
END
,date = '12082014'
WHERE user_rol IN ('student','assistant','admin')
AND cod_office = '17389551';
To Extend on #Trevedhek answer,
In case the update has to be done with non-unique keys, 4 queries will be need
NOTE: This is not transaction-safe
This can be done using a temp table.
Step 1: Create a temp table keys and the columns you want to update
CREATE TEMPORARY TABLE temp_table_users
(
cod_user varchar(50)
, date varchar(50)
, user_rol varchar(50)
, cod_office varchar(50)
) ENGINE=MEMORY
Step 2: Insert the values into the temp table
Step 3: Update the original table
UPDATE table_users t1
JOIN temp_table_users tt1 using(user_rol,cod_office)
SET
t1.cod_office = tt1.cod_office
t1.date = tt1.date
Step 4: Drop the temp table
In php, you use multi_query method of mysqli instance.
$sql = "SELECT COUNT(*) AS _num FROM test;
INSERT INTO test(id) VALUES (1);
SELECT COUNT(*) AS _num FROM test; ";
$mysqli->multi_query($sql);
comparing result to transaction, insert, case methods in update 30,000 raw.
Transaction: 5.5194580554962
Insert: 0.20669293403625
Case: 16.474853992462
Multi: 0.0412278175354
As you can see, multiple statements query is more efficient than the highest answer.
Just in case if you get error message like this:
PHP Warning: Error while sending SET_OPTION packet
You may need to increase the max_allowed_packet in mysql config file.
UPDATE Table1 SET col1= col2 FROM (SELECT col2, col3 FROM Table2) as newTbl WHERE col4= col3
Here col4 & col1 are in Table1. col2 & col3 are in Table2 I Am trying to update each col1 where col4 = col3 different value for each row
I did it this way:
<update id="updateSettings" parameterType="PushSettings">
<foreach collection="settings" item="setting">
UPDATE push_setting SET status = #{setting.status}
WHERE type = #{setting.type} AND user_id = #{userId};
</foreach>
</update>
where PushSettings is
public class PushSettings {
private List<PushSetting> settings;
private String userId;
}
it works fine
I have a database table and What I required to do is that,
I need to update the column with the column name 'Co15' of every rows according to the following conditions
Co15 = SAMPLE if Co13 = 'c1' AND Col2 = 'b4'
Co15 = LIST if Co13 = 'c6'
Currently I am running each update query separately as follows
UPDATE tblname SET Co15 = 'SAMPLE' WHERE Co13 = 'c1' AND Col2 = 'b4';
UPDATE tblname SET Co15 = 'LIST' WHERE Co13 = 'c6';
But wanted to know if there is any way where I could run only one update query all at once.
Thanks
Try this
UPDATE tblname SET Co15=
CASE
WHEN Co13 = 'c1' AND Col2='b4' THEN 'SAMPLE'
WHEN Co13 = 'c6' THEN 'LIST'
END
exactly getting the output to as following as:
UPDATE tblname
SET col5= CASE
WHEN col3 = 'c1' AND col2 = 'b4' THEN 'SAMPL'
WHEN col3 = 'c6' THEN 'LIST'
END
example: sqlfiddle to click here
Can someone tell me why this insert is failing but not giving me an error either? How do I fix this?
merge table1 as T1
using(select p.1,p.2,p.3,p.4,p.5 from #parameters p
inner join table1 t2
on p.1 = t2.1
and p.2 = t2.2
and p.3 = t2.3
and p.4 = t2.4) as SRC on SRC.2 = T1.2
when not matched then insert (p.1,p.2,p.3,p.4,p.5)
values (SRC.1,SRC.2,SRC.3,SRC.4,SRC.5)
when matched then update set t1.5 = SRC.5;
The T1 table is currently empty so nothing can match. The parameters table does have data in it. I simply need to modify this merge so that it checks all 4 fields before deciding what to do.
You can't select from a variable: from #parameters
See the following post: Using a variable for table name in 'From' clause in SQL Server 2008
Actually, you can use a variable table. Check it out:
MERGE Target_table AS [Target]
USING #parameters AS [Source]
ON (
[Target].col1 = [Source].col1
AND [Target].col2 = [Source].col2
AND [Target].col3 = [Source].col3
AND [Target].col4 = [Source].col4
)
WHEN NOT MATCHED BY TARGET
THEN INSERT (col1,col2,col3,col4,col5)
VALUES (
[Source].col1
,[Source].col2
,[Source].col3
,[Source].col4
,[Source].col5
)
WHEN MATCHED
THEN UPDATE SET [Target].col5 = [Source].col5;
i have the following hql query:
UPDATE TaskAssessment taskAssessment
SET taskAssessment.activeFlag = false
WHERE taskAssessment IN
(
SELECT taskAssessment2
FROM TaskAssessment taskAssessment2
Where taskAssessment2.activeFlag = true
AND taskAssessment2.patient.id
AND taskAssessment2.needsLevel.careNeed = :careNeed
)
but its giving me errors:
You can't specify target table 'TASK_ASSESSMENT' for update in FROM clause
could anyone help me to correct the query for mysql and hibernate. thanks in advance.
To resolve You can't specify target table 'TASK_ASSESSMENT' for update in FROM clause, rewrite the query to use JOIN instead of IN (in mysql you need to write something like this):
UPDATE TaskAssessment a
INNER JOIN TaskAssessment a2 ON (a2.id = a.id)
SET a.activeFlag = 0
WHERE a2.active_flag = 1 AND
a2.patient_id = :patient_id AND a2.needsLevel_careNeed = :careNeed