I need to set all values in certain columns...to 1 (where they are now NULL)
Can anyone help out with a little assist on this SQL query/command syntax?
I need to replace several columns where the SchoolID is 184 with a 1, something like this?
SELECT * FROM tblMembers WHERE SchoolID SET column = '1';
You need to use an UPDATE statement:
UPDATE tblMembers
SET column = '1'
WHERE SchoolID = '184'
You can set multiple columns at the same time:
UPDATE tblMembers
SET column = '1', column2 = 'somethingelse', column3 = 'somethingelse'
WHERE SchoolID = '184'
Related
I have a table called "allarmi_ingressi" in SQLite, with a lot of rows in it.
I want to create a query that changes the variable on my column "visto" to 1, if "visto=0", and to 0, if "visto=1".
This is what i made:
UPDATE allarmi_ingressi SET visto = '1' WHERE visto = '0'
Of course this modify every row in the column "visto";
I want to know if it's possible to modify it "selecting" it by the primary key, in my case "id_allarme".
In a SELECT query, you would use the WHERE clause to find rows with a specific id_allarme value.
The same WHERE clause can be used with UPDATE:
UPDATE allarmi_ingressi
SET visto = 1 - visto
WHERE id_allarme = ?;
Use CASE Expression
Query
update allarmi_ingressi
set visto = (
case visto when '1' then '0'
when '0' then '1'
else visto end
)
where id_allarme = __; -- id here
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 am not sure if its possible or not, Just want to know if it is. I have column plan_popular which has default value 0. Lets same i have a list :
Plan Name | plan_popular | amount
===================================
plan A 0 25.00
plan B 1 50.00
plan C 0 90.00
This is how i am doing:
$stmt = "update {CI}plans set plan_popular = 0";
$this->db->query($stmt);
$stmt2 = "update {CI}plans set plan_popular = 1 where plan_id = ?";
$this->db->query( $stmt2, array($plan_id) );
Now i have set the plan C to make. Now i want to reset it and want to make popular plan C to 1. What i am doing is running two queries, One i reset and make the plan_popular 0 and the second is get the update the plan C to 1 with there id. Is it possible in single query?
You can use an expression to determine the value to assign:
UPDATE {CI}plans
SET plan_popular = IF(plan_id = ?, 1, 0);
try this,
UPDATE {CI}plans
SET `plan_popular` = CASE `Plan Name`
WHEN 'plan C' THEN 1
ELSE 0
END
WHERE `Plan Name` IN((select `Plan Name` from {CI}plans where plan_popular=1 ) , 'plan C');
Updates can be expensive, what with manipulating locks, triggers and constraints firing, etc. In general, you want to avoid updating a field to the same value it already has. In English, if plan_id = variable and plan_popular is 0 then set it to 1 but if plan_id is any other value and plan_popular is 1 then set it to 0.
UPDATE {CI}Plans
SET plan_popular = if( plan_id = ?, 1, 0 )
where (plan_id = ? and plan_popular = 0)
or (plan_id <> ? and plan_popular = 1);
The where clause lets through only those rows that will actually be changed by the update. If this is a largish table, that can make quite a difference in response time. Logic is much less expensive than any actual operation that can performed in the database.
after reading all the "INSERT INTO" posts as well as the documentation, I am still unsure whether what I want is feasible or not.
I want to change the UPDATE below into an INSERT INTO, because I have many 100-thousands of them (speed issues):
UPDATE city c
SET
c.g17h = '3196504',
c.g17q = '2593487',
c.g17k = '0',
c.g17w = '0',
c.g17s = '0'
WHERE
p17t = 30 AND p17l = '30';
or
UPDATE city c
SET
c.g1h = '0',
c.g1q = '0',
c.g1k = '0',
c.g1w = '0',
c.g1s = '0'
WHERE
p1t = 1
AND p1l = '1';
However, my best solutions do not work:
INSERT INTO city (g17h, g17q, g17k, g17w, g17s)
SELECT
'3196504',
'2593487',
'0',
'0',
'0'
FROM valuestoretab
WHERE
p17t = 30
AND p17l = '30';
This is of course because my WHERE condition can only be satisfied in the first table (city) but not in the second one which is just a table of values, whereas the city table is a data set where each id has particular values for p17t, p17l and so on.
For clarification:
The first table (city) looks like
cityid1, ownerid1, islandid1, p17t, p17l
cityid2, ownerid2, islandid2, p17t, p17l
with different values for each row for p17t and p17l.
So, my questions would be:
1. Is it at all possible to write a INSERT-Query with a WHERE condition for the table that is being inserted into?
2. If no, do I have to stick to my UPDATE or is there another (fast!) solution?
Thanks to the community!
litotes
To give a quick answer insert with a select statement is possible
Insert INTO MyTable (Val1, Val2)
Select
SomeValue,
AnotherValue
From MyOtherTable
Where Date = Getdate()
On the other hand, you can also update many records like in the following example:
Update t1
Set
t1.Val1 = t2.SomeValue,
t1.Val2 = t2.AnotherValue
From MyTable t1
Inner join MyOtherTable t2 ON t1.PK = t2.FK
where t2.Date = getdate()
EDIT:
When i read the following query, I presume p17t and p17l are from the valuestoretab.
UPDATE city c
SET
c.g17h = '3196504',
c.g17q = '2593487',
c.g17k = '0',
c.g17w = '0',
c.g17s = '0'
WHERE
p17t = 30 AND p17l = '30';
==> changed this into:
UPDATE c
SET
c.g17h = '3196504',
c.g17q = '2593487',
c.g17k = '0',
c.g17w = '0',
c.g17s = '0'
FROM City c, ValueStoreTab v
WHERE
c.SomeCol = v.SomeCol -- Here, your relation must exist!
AND v.p17t = 30 AND v.p17l = '30';
I got the following query :
INSERT INTO contracts_settings (contract_id, setting_id, setting_value)
VALUES (:contract_id, (
SELECT setting_id
FROM settings
WHERE setting_type = :setting_type
AND setting_name = :setting_name
LIMIT 1
), :setting_value)
ON DUPLICATE KEY UPDATE setting_value = :setting_value
The value with the prefix : is replaced with data using PHP PDO::bindBalue.
If the inner query find nothing (it return NULL) but also INSERT a NULL statement. How to avoid that ?
Thanks.
Convert the INSERT ... VALUES syntax to INSERT ... SELECT:
INSERT INTO contracts_settings
(contract_id, setting_id, setting_value)
SELECT
:contract_id,
setting_id,
:setting_value
FROM settings
WHERE setting_type = :setting_type
AND setting_name = :setting_name
LIMIT 1
ON DUPLICATE KEY UPDATE
setting_value = :setting_value ;