Assume I have a query that returns a result set of columns A and B from table First_Table. I want to limit the result set to those columns if the value of column X in table Second_Table is 0, and I want to add column C from table First_Table if the value of column X is 1.
The problem is easily resolved using a Python for example whereby I just have a variable as an empty string if value in column X is 0 or it would be equal to the string 'First_Table.ColumnC AS [Dynamic Value],', and I just format the sql in the script accordingly.
If Else solution is not an elegant way because I have multiple columns to add dynamically depending on multiple values...
I am just looking for some ideas on directions.. I have been looking at this for a while, might be bogged up
Dynamic sql is the best way to resolve this as suggested in the comments.
Related
In application I am working on.
I have to input from user through excel and first put it in temporary sql table & then from temporary table to final target table.
My query is failing while putting data from temporary table to target table.
Because some values present in temporary table are out of range of columns in target table.
How can I check if values present in temporary table are within range of column of target table?
I have to check like this
20 < len(temporary_table.column1) < 50
or is there any better way
If you are using SQL server you can use below query for data checking.
temporary_table.column1 between 20 and 50
If you are looking based on the column max length. For example, your columns have datatype varchar(100) then you can use the condition like this
where len(temporary_table.column1)<=100
Extending on the above answer you can just use col_length instead of hard coding the value on the target column. This makes it more automated and less prone to mistakes (entering a value mistakenly)
where len(temporary_table.column1) <= COL_LENGTH ( 'target_table' , 'column1' )
When I am trying to update a column with character datatype using update statement. It says 0 rows update and does not throw any error. As the number of columns are much i tried using where clause using specific column out of it...where it updates the row.
Issue is when all the columns are used to alter the value, it gives back 0 rows updated. I have to automate it in vba code/tool so that it could update using all the rows. I identified the columns using which the value is not being updated but there is no error return.
It only says:
0 rows updated.
But what is wrong with that specific column(datatype...decimal).
Please help. I have searched whole internet but no results.
If you are trying to update a specific value in your database and only that one, you may have a rounding issue. This mean the value you see is not the exact value stored.
So you may try to update it with a specific range.
First select what you want to update:
select rowid from table_1
where val_x between <x>-<upsilon> and <x>+<upsilon>;
Update if you have only one value;
update table_1 set val_x = <new_val>
where val_x between <x>-0.001 and <x>+0.001
;
(otherwise, if more than 1 value, decrease <upsilon> to 0.0001, etc.)
Hope it helps
I want to update a table with complex entries in a column and just a clause in the column without effecting other values.
Want to update #Rule number=0# to #Rule number=1# but without affecting other values in the column. Is this possible?
Are you looking for replace()? If dynamic_attributes is a string:
update t
set dynamic_attributes = replace(dynamic_attributes,
'#Rule number=0#',
'#Rule number=1#'
)
where dynamic_attributes like '%#Rule number=0#%';
Note: Strings may not be the best way to store such a list. You should consider a table with one row per customer_id and dynamic attribute.
Here it is:
UPDATE A
SET A.dynamic_attributes = REPLACE(A.dynamic_attributes,'#Rule number=0#','#Rule number=1#')
FROM yourtable AS A
WHERE A.dynamic_attributes LIKE '%#Rule number=0#%'
the following function deletes all blanks in a text or varchar column and returns the modified text/varchar as an int:
select condense_and_change_to_int(number_as_text_column) from mytable;
This exact query does work.
Though my goal is to apply this function to all rows of a column in order to consistently change its values. How would I do this? Is it possible with the UPDATE-clause, or do i need to do this within a function itself? I tried the following:
UPDATE mytable
SET column_to_be_modiefied = condense_and_change_to_int(column_to_be_modiefied);
Basically i wanted to input the value of the current row, modify it and save it to the column permanantly.
I'd welcome all ideas regarding how to solve scenarios like these. I'm working with postgresql (but welcome also more general solutions).
Is it possible with an update? Well, yes and sort-of.
From your description, the input to the function is a string of some sort. The output is a number. In general, numbers should be assigned to columns with a number type. The assumption is that the column in question is a number.
However, your update should work. The result will be a string representation of the number.
After running the update, you can change the column type, with something like:
alter table mytable alter column column_to_be_modiefied int;
I have created a lookup table in Access to provide the possible values for a column. Now I need to update this column with the data it had before I converted the column. I am unable to figure out a SQL Query that will work. I keep getting the error "An UPDATE or DELETE query cannot contain a multi-valued field." My research has suggested that I just need to set the value of the column but this always updates 0 records:
UPDATE [table_name] SET [column_name].Value = 55 WHERE [table_name].ID = 16;
I know this query will work if I change it to update a text column, so it is definitely a problem with just this column.
If you're adding a value to your multi-valued field, use an append query.
INSERT INTO table_name( [column_name].Value )
VALUES (55)
WHERE ID = 16;
If you want to change one particular value which exists in your multi-valued field, use an UPDATE statement. For example, to change the 55 to 56 ...
UPDATE [table_name]
SET [column_name].Value = 56
WHERE [column_name].Value = 55 And ID = 16;
See Using multivalued fields in queries for more information.
I have figured this out! It certainly was counter-intuitive! You have to use an INSERT statement to do the update.
-- Update a record with a multi-valued field that has no value
INSERT INTO [table_name] ( [[column_name].[Value] )
VALUES(55)
WHERE [table_name].ID = 16;
This confused me because I was expecting an UPDATE statement. I think it actually inserts a record into a hidden table that is used to associate multiple values with this column.
I am working with Sharepoint, I created the tables as multi-value fields, ran into the error with my INSERT INTO statement, went back to Sharepoint to change to non-multi-value fields, but that didn't fix it.
Recreated the table without using multi-value fields, and the INSERT INTO worked just fine.
do not use the .value part
UPDATE [table_name] SET [column_name] = 55 WHERE [table_name].ID = 16;
INSERT INTO Quals (cTypes.[value])
SELECT Quals_ContractTypes.ContractType
FROM Quals_ContractTypes
WHERE (Quals.ID = Quals_ContractTypes.ID_Quals);
I gotta say I didn't understand very well your problem but I saw something strange in your query. Try this:
UPDATE [table_name] SET [column_name]= 55 WHERE [table_name].ID = 16;
UPDATE:
Look at this link: it has an example
UPDATE Issues
SET Issues.AssignedTo.Value = 10
WHERE (((Issues.AssignedTo.Value)=6)
AND ((Issues.ID)=8));
NOTES
You should always include a WHERE
clause that identifies only the
records that you want to update.
Otherwise, you will update records
that you did not intend to change. An
Update query that does not contain a
WHERE clause changes every row in the
table. You can specify one value to
change.
The Multi-Valued field refers to Access databases that have tables with columns, that allow you to select multiple values, like a Combo Checkbox list.
THOSE are the only Access types that SQL cannot work with. I've tested all Access lookup possibilities, including hard-coded values, and lookup tables. They work fine, but if you have a column that has the Allow Multiple select options, you're out of luck. Even using the INSERT INTO as mentioned below, will not work as you'll get a similar but different error, about INSERTing into multi-valued fields.
As mentioned it's best to avoid using such tables outside of Access, and refer to a table specifically for your external needs. Then write a macro/vba script to update the real tables with the data from the "auxiliary" table.