I use a regex in my SQL statements for an app that look like this
SELECT * FROM table WHERE id = {{REPLACEME}}
However, sometimes I'm not giving a parameter to replace that string with. Is there a way to replace it with something that matches anything. I tried *, but that does not work.
SELECT * FROM table WHERE id = id will match all rows that have non-null id
SELECT * FROM table WHERE id = id OR id IS NULL will match all rows.
id is probably a primary key, so you can probably use the former.
Replace {{REPLACEME}} with
[someValidValueForYouIdType] OR 1=1
I can only describe my solution with an example. The #AllRec is a parameter:
Declare #AllRec bit
set #AllRec = {0|1} --as appropriate
SELECT *
FROM table
WHERE
(
id = {{REPLACEME}}
and #AllRec = 0
) OR (
#AllRec = 1
)
In this solution, if #AllRec is 1 then everything is returned, ignoring the id filter. If #AllRec is zero, then the id filter is applied and you get one row. You should be able to quickly adapt this to your current regex solution.
Using the Regex-Replace option opens you up to SQL Injection attacks.
Assuming your language has support for parameterized queries, try this modified version of Jacob's answer:
SELECT * FROM table WHERE (id = #id OR #id IS NULL)
The catch is that you'll always have to provide the #id value.
SELECT field1, field2
FROM dbo.yourTable
WHERE id = isnull(#var, id)
Not sure what language your using, and this code kind of scares me but...
var statement = "SELECT * FROM table";
If REPLACEME is not empty Then
statement += " WHERE id = {{REPLACEME}}"
End If
Related
The code snippet below is what I'm trying to achieve, but I'm having trouble making it work. If the parameter that gets passed into the procedure is null, I want to only return the rows with a WHERE clause IS NULL, but if there is a value, I want to return the rows that are equal to the value passed in. Dynamic SQL seems like it would work, but I'm curious if there's an easier way I'm missing. Thanks in advance.
PARAM:
#id varchar(10) = '123456789'
SELECT *
FROM TABLE T
WHERE
CASE
WHEN #id IS NULL THEN (id IS NULL)
ELSE id = #id
END
The logic you want is:
WHERE (#id IS NULL AND id IS NULL) OR
id = #id
You're trying to use a CASE expression like a Case (Switch) statement. Switches don't exist in T-SQL, and a CASE expression returns a scalar value not a boolean result.
Don't, however, use CASE expressions in the WHERE, use proper Boolean logic:
SELECT *
FROM YourTable YT
WHERE (ID = #ID
OR (ID IS NULL AND #ID IS NULL))
My script has a variable that does not always contain a value. If there is a value, I need an extra WHERE clause.
DECLARE #identityUserIds NVARCHAR;
SELECT #identityUserIds = (SELECT TOP (1) [userIdsCsv] FROM [identityUsers])
SELECT *
FROM [Users]
-- IF (!ISNULL(#identityUserIds) OR #identityUserIds != '')
WHERE [ID] in (#identityUserIds)
-- ELSE (no extra condition)
How can I do that?
A common way to do this is:
... where #identityUserIds is null or ID in (#identityUserIds)
I think this can simply be done with an OR:
SELECT *
FROM [Users]
WHERE Len(ISNULL(#identityUserIds,''))=0
OR [ID] IN (#identityUserIds)
But note that #Rhumborl's comment is correct, the IN statement will not work with a string. Unfortunatly I have no immediate solution for that problem.
...where ID in (ISNULL(#identityUserIds,ID))
I have a column, sort_order in a table that contains a string of numbers, a delimiter and some P values:
1150||P||1168||1144||1149||1147||1164||1152||P||1148||1162||1163||P||1156||1157||1154||
I would like to replace any P values in this string with another value from the event_tile_id column of another table.
So far I've drafted this SQL below with no luck. What changes can I make to this Query to get the effect I need?
`SELECT sort_order,
(
REPLACE(sort_order,'P',
(SELECT TOP 1 event_tile_id
FROM daily_email_sales_today)
)
)
as sort_order
FROM daily_email_preview`
Removed "default_SaleID" from Query. Replace should now have 4 arguments.
This is how I would do it.
Since you don't have any joins, why not do a simpler update query using a static value?
DECLARE #update VARCHAR(100)
SET #update = (SELECT TOP 1 event_tile_id FROM daily_email_sales_today)
update daily_email_preview
SET sort_order = replace(sort_order,'P', #update)
Or even,
update daily_email_preview
SET sort_order = replace(sort_order,'P', '<new value>')
Assuming you are using SQL Server.
Along the same thought process as #Eric_Hauenstein if you are running this in a TSQL process:
declare #rSTR as varchar(50)
SELECT TOP 1 #rSTR = event_tile_id FROM daily_email_sales_toda
SELECT sort_order, REPLACE(sort_order,'P', #rSTR) as sort_order
FROM daily_email_preview
I have a situation where I want to search for a field in the where clause only if the bit variable is 1 else ignore it.
#Active bit = 0
select * from Foo where firstname = 'xyz' and
if(#active=1)
then search on the Active column else ignore the filtering on the Active column. How can I have that in a simple condition instead of checking each parameter seperately and then building the where clause
Just simple logic will usually suffice:
select * from Foo where firstname = 'xyz' and
(#Active = 0 or Active = <filter condition>)
For general advice about writing code for arbitrary search conditions, you could do worse than read Erland Sommarskog's Dynamic Search Conditions in T-SQL
it seems like Active is the Actual Column as well in your table.
using Case stmt you can make the search efficient as it will use appropriate indexes you may have on this table.
DECLARE #Active BIT=0
SELECT *
FROM Foo
WHERE firstname = 'a'
AND active = CASE WHEN #Active=1 THEN #Active ELSE Active END
How about:
DECLARE #Active bit
if #Active = 1
BEGIN
(select * from Foo where firstname = 'bar' and Active = --condition)
END
else
BEGIN
(select * from Foo where firstname = 'bar')
END
of course, something will have to set the value for #Active somewhere between the declaration and the if...else statement.
you can write this as below
select * from Foo where firstname = 'xyz' and (#isactive=0 or (some conditions))
I have a small select query which picks data from a table as per the parameter passed to a procedure.
DECLARE #flgParam bit
.
.
SELECT *
FROM tablename
WHERE flgRequired like <If #flgparam is 0 then 1 or zero , Else 1>
what is the best way to construct the where clause
I'm thinking something like this:
SELECT *
from tablename
where #flgparam is null or #flgcolumnval = #flgparam;
#flgparam is declared as a bit, so it can only take on the values of NULL, 0, and 1.
EDIT:
I'm trying to understand the logic. Adapted for the right names:
SELECT *
from sample
where (#flgparam = 0 and flgRequired is not null) or
(coalesce(#flgparam, 1) = 1 and flgRequired = 1)
The like is unnecessary; you can do strict equality.
A bit rough, but it should work, based on requirements:
select
S.itemname
,S.flgrequired
from
sample S
where
(S.flgRequired >= #flgParam)
Tested on sqlfiddle.
You cant use variables to substitute columns in the querys, to achieve that you should create your query as a string #QUERY and execute it using exec #QUERY