In my PostgreSQL database I have table that is inside import schema. When I want to get all data from the column I do:
select * from import.master_plan
This query works fine. But when I try to for example get only title column values:
select import.master_plan.title from import.master_plan;
it returns:
ERROR: column master_plan.title does not exist
LINE 1: select import.master_plan.title from import.master_plan;
^
HINT: Perhaps you meant to reference the column "master_plan. title".
I've also tried:
select title from import.master_plan;
but this also not works. I'm using PostgreSQL 10. How can I fix that?
I would suggest that you use a table alias instead:
select mp.title
from import.master_plan mp;
This is much easier to read and to type.
Judging from the error message, though, the name seems to have leading spaces. Something like:
select mp." title"
from import.master_plan mp;
might work. If this is the case, alter the table and rename the column.
Related
Looks like we've loaded some snowflake tables via ELT with "TO, FROM" as column names and they are both classic functions in any sql tool
Whenever I run a query for specifically those columns, there's always an error - how do I fix it apart from changing column names? Don't want to change column names as ELT process always happens from mongoDB via log based replication (stitch data)
select * - works perfectly , all other columns work too. Just "to" , "from" is the issue - should that never be used a columns?
select to, from from table limit 10 ; // tested [to, "to", 'to'] - none work
Error: SQL compilation error: error line 1 at position 7 invalid identifier '"to"'
Any ideas how to fix this apart from source column change or snowflake column changes?
Snowflake uses the standard double quotes to escape identifiers. However, when identifiers are escaped, the case of the letters matters, So, these are not the same:
select "to"
select "To"
select "TO"
You need to choose the one that is correct for your column names.
In addition spaces matter, so these are not the same:
select "to "
select " to"
select "to"
That is, what looks like to might be something else. You need to know what that is to escape the name properly.
If you can't figure them out, there is a trick to create a view to give the table reasonable names. Something like this:
create view v_t (to_date, from_date, . . .) as
select *
from t;
You need to be sure to include all the column names in the table in the column name list, in the same order as they are in the table. Then you can use the view with reasonable names.
i have a table whose name is like. But whenever i have to select data from like, i was getting this error, i figured it out public.like..but when i try to join two tables
SELECT *
FROM frame
INNER JOIN public.like
ON like.takerId = frame.likeId;
i get this error
ERROR: syntax error at or near "."
LINE 4: ON like.takerId = frame.likeId;
i also use public prefix but it throws
ERROR: column like.takerid does not exist
LINE 4: ON public.like.takerId = frame.likeId;
^
HINT: Perhaps you meant to reference the column "like.takerId".
even if it is saying column like.takerid does not exist , then why it gives me HINT: Perhaps you meant to reference the column "like.takerId". I dont know, i think it is problem with like table name, like is a sql syntax, and it assumes like and a sql syntax and throwing me error. Should I change my table name? Or is there any way to make sql case sensetive or how can i tell sql to ignore like. public.like is not working for joining table.
As like is a reserved keyword, you need to use double quotes for each occurance of it (unless it's prefixed with the schema name as you found out)
SELECT *
FROM frame
JOIN public.like ON "like".takerId = frame.likeId;
Or
SELECT *
FROM frame
JOIN "like" ON "like".takerId = frame.likeId;
Or use an alias
SELECT *
FROM frame f
JOIN "like" l ON l.takerId = f.likeId;
But in the long run you should find a different name for the table that does not require quoting.
You should definitely chose another name for your table. LIKE is a reserved command, and it is considered a bad practice to use it, although possible by using ", e.g.
CREATE TABLE public."like" (id int);
INSERT INTO public."like" VALUES (42);
SELECT * FROM "public.like"
EDIT: As pointed out by #a_horse_with_no_name, specifying a schema in temporary tables won't work (check db<>fiddle), so only the table name should be between double quotes as corrected in the snippet above. For temporary tables just omit the schema:
CREATE TEMPORARY TABLE "like" (id int);
INSERT INTO "like" VALUES (42);
SELECT * FROM "like"
Demo: db<>fiddle
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)
When I look at a view/table, I can get the column names using the following SQL query:
SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME='table'
Obviously, this will work to show columns for tables; but it does not work for functions. Is there an easy way (besides getting one record from a function, and manually parsing it) to get the column names returned by a function?
Does this help?
SELECT *
FROM INFORMATION_SCHEMA.ROUTINE_COLUMNS
I'm unsure if this works for inline TVFs
How can I add a column in an SQLite table if and only if the same column does not exist in the table?
Using ALTER TABLE I am able to create a new column but want to know how to check whether that column already exists in the table or not?
SQLite returns an error like "no such column: foo" if the table doesn't contain the column:
select foo from yourTable limit 1
Also you can get the create-table statement:
select sql from sqlite_master where tbl_name = 'YourTableName'
and then parse the result, looking for the column-name. I don't know of an elegant way to query the list of columns for a specified table, though one may exist.
Also if you attempt to do this:
alter table YourTable add column foo {column-def whatever it is}
you get an error from SQLite if the column already exists. You could trap that error too.
Finally you could do this:
select sql from sqlite_master
where tbl_name = 'YOURTABLE' and sql like '%"foo" CHAR%'; -- or whatever type
and if the specified table contains the column which is surrounded by double-quotes in the query, and with the type you have specified, you will get a result, otherwise an empty set. Specifying the datatype ensures that your LIKE substring match occurs on a column-name.
There's no way (that I know of) to do it all in a single SQLite query. You must use application code to manage the If/Elseness.
Check if table exists or not:
select count(*) from sqlite_master where type = 'table' and name = MyTable';
Check if column exists in table or now
pragma table_info(thumbnail);
However, a better approach may be explicit database schema updates based on schema versions your application maintains (e.g. specific alter table statement to go from schema version 1 to 2):
pragma user_version;
It seems like that it is impossible to do checking if the column not exists and addindg the new column in one command, because Sqlite don't support "IF NOT EXISTS" for column. "IF NOT EXISTS" works only on table.
Here is what I will do:
rev = ExecuteStatement("SELECT columnNamexx FROM tableNamexx limit 1;");
if(rev != SQLITE_OK){ // add col to table
ExecuteStatement("ALTER TABLE tableNamexx ADD COLUMN columnNamexx INTEGER DEFAULT 0;");
}
You can view the table columns by using '.schema tableName'