I want to append new rows to a table-1 d:\dl based on the equality constraint lower(rdl.subdir) = lower(tr.n1), where rdl and tr would be prospective aliases for f:\rdl and f:\tr tables respectively.
I get a function name is missing ). message when running the following command in VFP9:
INSERT INTO d:\dl SELECT * FROM f:\rdl WHERE (select LOWER(subdir)FROM f:\rdl in (select LOWER(n1) FROM f:\tr))
I am using the in syntax, instead of the alias based equality statement lower(rdl.subdir) = lower(tr.n1) because I do not know where to define aliases within this command.
In general, the best way to get something like this working is to first make the query work and give you the results you want, and then use it in INSERT.
In general, in SQL commands you assign aliases by putting them after the table name, with or without the keyword AS. In this case, you don't need aliases because the ones you want are the same as the table names and that's the default.
If what you're showing is your exact code and you're running it in VFP, the first problem is that you're missing the continuation character between lines.
You're definitely doing too much work, too. Try this:
INSERT INTO d:\dl ;
SELECT * ;
FROM f:\rdl ;
JOIN f:\tr ;
ON LOWER(rdl.subdir) = LOWER(tr.n1)
Related
I have a table named Posts I would like to count and profile in Snowflake using the current Snowsight UI.
When I return the results via EXPLAIN using TABLULAR I am able to return the set with the combination of TABLE, RESULT_SCAN, and LAST_QUERY_ID functions, but any predicate or filter or column reference seems to fail.
Is there a valid way to do this in Snowflake with the TABLE function or is there another way to query the output of the EXPLAIN using TABLULAR?
-- Works
EXPLAIN using TABULAR SELECT COUNT(*) from Posts;
-- Works
SELECT t.* FROM TABLE(RESULT_SCAN(LAST_QUERY_ID())) as t;
-- Does not work
SELECT t.* FROM TABLE(RESULT_SCAN(LAST_QUERY_ID())) as t where operation = 'GlobalStats';
-- invalid identifier 'OPERATION', the column does not seem recognized.
Tried the third example and expected the predicate to apply to the function output. I don't understand why the filter works on some TABLE() results and not others.
You need to double quote the column name
where "operation"=
From the Documentation
Note that because the output column names from the DESC USER command
were generated in lowercase, the commands use delimited identifier
notation (double quotes) around the column names in the query to
ensure that the column names in the query match the column names in
the output that was scanned
I feel like this should be simple but I'm relatively unskilled in SQL and I can't seem to figure it out. I'm used to wrangling data in python (pandas) or Spark (usually pyspark) and this would be a one-liner in either of those. Specifically, I'm using Snowflake SQL, but I think this is probably relevant to a lot of flavors of SQL.
Essentially I just want to trim the first character off of a specific column. More generally, what I'm trying to do is replace a column with a substring of the same column. I would even settle for creating a new column that's a substring of an existing column. I can't figure out how to do any of these things.
On obvious solution would be to create a temporary table with something like
CREATE TEMPORARY TABLE tmp_sub AS
SELECT id_col, substr(id_col, 2, 10) AS id_col_sub FROM table1
and then join it back and write a new table
CREATE TABLE table2 AS
SELECT
b.id_col_sub as id_col,
a.some_col1, a.some_col2, ...
FROM table1 a
JOIN tmp_sub b
ON a.id_col = b.id_col
My tables have roughly a billion rows though and this feels extremely inefficient. Maybe I'm wrong? Maybe this is just the right way to do it? I guess I could replace the CREATE TABLE table2 AS... to INSERT OVERWRITE INTO table1 ... and at least that wouldn't store an extra copy of the whole thing.
Any thoughts and ideas are most welcome. I come at this humbly from the perspective of someone who is baffled by a language that so many people seem to have mastery over.
I'm not sure the exact syntax/functions in Snowflake but generally speaking there's a few different ways of achieving this.
I guess the general approach that would work universally is using the SUBSTRING function that's available in any database.
Assuming you have a table called Table1 with the following data:
+-------+-----------------------------------------+
Code | Desc
+-------+-----------------------------------------+
0001 | 1First Character Will be Removed
0002 | xCharacter to be Removed
+-------+-----------------------------------------+
The SQL code to remove the first character would be:
select SUBSTRING(Desc,2,len(desc)) from Table1
Please note that the "SUBSTRING" function may vary according to different databases. In Oracle for example the function is "SUBSTR". You just need to find the Snowflake correspondent.
Another approach that would work at least in SQLServer and MySQL would be using the "RIGHT" function
select RIGHT(Desc,len(Desc) - 1) from Table1
Based on your question I assume you actually want to update the actual data within the table. In that case you can use the same function above in an update statement.
update Table1 set Desc = SUBSTRING(Desc,2,len(desc))
You didn't try this?
UPDATE tableX
SET columnY = substr(columnY, 2, 10 ) ;
-Paul-
There is no need to specify the length, as is evidenced from the following simple test harness:
SELECT $1
,SUBSTR($1, 2)
,RIGHT($1, -2)
FROM VALUES
('abcde')
,('bcd')
,('cdef')
,('defghi')
,('e')
,('fg')
,('')
;
Both expressions here - SUBSTR(<col>, 2) and RIGHT(<col>, -2) - effectively remove the first character of the <col> column value.
As for the strategy of using UPDATE versus INSERT OVERWRITE, I do not believe that there will be any difference in performance or outcome, so I might opt for the UPDATE since it is simpler. So, in conclusion, I would use:
UPDATE tableX
SET columnY = SUBSTR(columnY, 2)
;
I have 2 sqlite databases, and I'm trying to insert data from one database to another. For example, "db-1.sqlite" has a table '1table' with 2 columns ('name', 'state'). Also, "db-2.sqlite" has a table '2table' with 2 columns ('name', 'url'). Both tables contain a list of 'name' values that are mostly common with each other but randomized, so the id of each row does not match.
I want to insert the values for the 'url' column into the db-1's table, but I want to make sure each url value goes to its corresponding 'name' value.
So far, I have done this:
> sqlite3 db-1.sqlite
sqlite> alter table 1table add column url;
sqlite> attach database 'db-2.sqlite' as db2;
Now, the part I'm not sure about:
sqlite> insert into 1table(url) select db2.2table.url from db2.2table where 1table.name==db2.2table.name
If you look at what I wrote above, you can tell what I'm trying to accomplish, but it is incorrect. If I can get any help on the matter, I'd be very grateful!!
The equality comparison operator in SQL is =, not ==.
Also, I suspect that you should be updating 1table, rather then inserting in it.
Finally, your table names start with digits, so you need to escape them.
This SQL should work better:
update `1table`
set url = (select db2.`2table`.url
from db2.`2table`
where `1table`.name = db2.`2table`.name);
I know you cannot use a alias column in the where clause for T-SQL; however, has Microsoft provided some kind of workaround for this?
Related Questions:
Unknown Column In Where Clause
Can you use an alias in the WHERE clause in mysql?
“Invalid column name” error on SQL statement from OpenQuery results
One workaround would be to use a derived table.
For example:
select *
from
(
select a + b as aliased_column
from table
) dt
where dt.aliased_column = something.
I hope this helps.
Depending on what you are aliasing, you could turn it into a user defined function and reference that in both places. Otherwise your copying the aliased code in several places, which tends to become very ugly and means updating 3+ spots if you are also ordering on that column.
I'm trying to create a sql query, but there is this error:
Ambiguous column name 'description'.
Its because this column occurs in both tables.
if I remove the description from the query, it works.
I tried to rename the description-field "AS description_pointer", but the error still occurs.
SELECT TOP 1000 [activityid]
,[activitytypecodename]
,[subject]
,[regardingobjectid]
,[contactid]
,[new_crmid]
,[description] AS description_pointer
FROM [crmtestext_MSCRM].[dbo].[FilteredActivityPointer] as I
Left JOIN [crmtestext_MSCRM].[dbo].[FilteredContact]
ON I.[regardingobjectid] = [crmtestext_MSCRM].[dbo].[FilteredContact].[contactid]
WHERE new_crmid not like '%Null%' AND activitytypecodename like '%E-mail%'
Both tables coming into play in the query have a column named description. You RDBMS cannot guess which column table you actually want.
You need to prefix the column name with the table name (or table alias) to disambiguate it.
Bottom line, it is a good practice to always prefix column names with table names or aliases as soon as several tables come into play in a query. This avoids the issue that you are seeing here and make the queries easier to understand for the poor souls that have no knowledge of the underlying schema.
Here is an updated version of your query with table aliases and column prefixes. Obviously you need to review each column to put the correct alias:
SELECT TOP 1000
i.[activityid]
,i.[activitytypecodename]
,i.[subject]
,c.[regardingobjectid]
,c.[contactid]
,c.[new_crmid]
,c.[description] AS description_pointer
FROM [crmtestext_MSCRM].[dbo].[FilteredActivityPointer] as i
Left JOIN [crmtestext_MSCRM].[dbo].[FilteredContact] as c
ON i.[regardingobjectid] = c.[contactid]
WHERE i.new_crmid not like '%Null%' AND i.activitytypecodename like '%E-mail%'