If I do the following in SSMS 2008 r2, using T-SQL:
SELECT TOP 1 [col1]
FROM [table1] AS ourResult
The alias column header ourResult works as expected.
However, if I do the very similar:
SELECT MIN([Date])
FROM [table1] AS min_date1
the alias for the column header does not work and instead there is:
(No column name)
Is there a fix for this somewhat simple situation?
This query
SELECT TOP 1 [col1]
FROM [table1] AS ourResult
will return col1 as the columnheader
but this query
SELECT MIN([Date])
FROM [table1] AS min_date
will return (No column name) because you wrap the actual column with a function therefore you need a new name or keep the same one by doing this
SELECT MIN([Date]) as minDate
FROM [table1] AS min_date
the From clause with "as" is the alias for the table and not the column.
Related
I have the following query
SELECT DISTINCT ON (user_id) user_id, timestamp
FROM entries
WHERE user_id in (1,2)
AND entry_type IN(
SELECT jsonb_array_elements_text(
SELECT entry_types
FROM users INNER JOIN orgs
ON org_id = orgs.id
WHERE users.id = 1
)
);
I'm getting a syntax error at or near select
syntax error at or near "select" LINE 1: ... entry_type in( select
jsonb_array_elements_text(select ent.
The field entry_types is a JSONB field, so I am trying to convert it to text in order to use it in the WHERE IN clause.
PostgreSQL 13.0
This sub-query within jsonb_array_elements_text
SELECT entry_types
FROM users INNER JOIN orgs
ON org_id = orgs.id
WHERE users.id = 1
Returns a single JSONB entry like this:
entry_types
--------------------------------------------
["type1", "type2", "type3"]
I'm simply trying to use the array of text values returned there as the criteria inside the WHERE IN clause.
The syntax error seems to point somewhere else, so maybe I am wrong, but the problem I see is a missing pair of parentheses around the subquery:
jsonb_array_elements_text((SELECT ...))
I have two tables that am using union to combine the result-set of them my problem here is Each SELECT statement within UNION must have the same number of columns and data types, I don't have the same number of columns so am creating null columns
select
d.deal_id as order_id,
EXISTS(select * from table1 c where d.user_id = c.user_id) as IsUser, --this returns boolean value
from table 1 c
union
select
cast(o.id as varchar) as order_id,
coalesce('No_user'::text,'0'::text) as IsUser, --i get an error :UNION types boolean and character varying cannot be matched
from table2 o
how can I create a null column in table2 that matches the boolean data type of the table1
how can I create a null column in table2 that matches the boolean data type of the table1
By putting NULL into the SELECT list of the second query.
Generally (in SQL) the datatype for the column is dictated by the first query in the union set and other queries must match. You don't need column aliases for subsequent queries either, but they may help make a query more readable:
select
d.deal_id as order_id,
EXISTS(select * from table1 c where d.user_id = c.user_id) as IsUser, --this returns boolean value
from table 1 c
union
select
cast(o.id as varchar) as order_id,
null --IsUser
from table2 o
If you have a case where the type of the column in the first query is different to what you want in the output, you cast the first column:
select 1::boolean as boolcol
UNION
select true
This will ensure that the column is boolean, rather than giving a "integer and bool cannot be matched". Remember also that, should you need to, NULL can be cast to a type, e.g. select null::boolean as bolcol
I am trying to update column3, based on a calculation which is happening between column1 and column2. The theory is relatively simple, however I seem to be struggling with CTE's. If column1 is not null, then column1 * AVG(column2) gets put in column3.
I have searched the forums and tried a few different methods, including CTE and standard UPDATE queries. I seem to be making a mistake.
WITH cte_avg1 AS (
SELECT "column1" * AVG("column2") AS avg
FROM table1
)
UPDATE table1
SET "column3" = cte_avg1.avg
FROM cte_avg1
WHERE "column1" IS NOT NULL;
The error message which I am getting is as follows;
ERROR: column must appear in the GROUP BY clause or be used in an aggregate function
LINE 5: SELECT "column1" * AVG("column2"...
In an aggregating query all columns after SELECT must either be in the GROUP BY clause or a parameter to an aggregation function. Move the multiplication out of the CTE.
WITH cte_avg1
AS
(
SELECT avg(column2) avg
FROM table1
)
UPDATE table1
SET column3 = column1 * cte_avg1.avg
FROM cte_avg1
WHERE column1 IS NOT NULL;
I have a Postgresql table where I have 2 fields i.e. ID and Name ie column1 and column2 in the SQLFiddle. The default record_count I put for a particular ID is 1. I want to get the record_count for column 1 and sum that record_count by column1.
I tried to use this query but somehow its showing some error.
select sum(column_record) group by column_record ,
* from (select column1,1::int4 as column_record from test) a
Also find the Input/Output screenshot in the form of excel below :
SQL Fiddle for the same :
http://sqlfiddle.com/#!15/12fe9/1
If you're using a window function (you may want to use normal grouping, which is "a lot" more faster and performant), this is the way to do it:
-- create temp table test as (select * from (values ('a', 'b'), ('c', 'd')) a(column1, column2));
select sum(column_record) over (partition by column_record),
* from (select column1, 1::int4 as column_record from test) a;
I need to run the following query to extract the values of my raster records in a specific point.
select st_value((select rast from mytable),
(select st_GeomFromText('POINT(30.424 -1.978)', 4326)))
But I encounter with the following error:
ERROR: more than one row returned by a subquery used as an expression
SQL state: 21000
It needs just one record for this function but I need to extract values of all of records.
If a subquery returns multiple rows, you must either use it in a common table expression (CTE / WITH query) and FROM alias, or use FROM (SELECT ...) alias. In this case, though, it looks like it's simpler than that:
select st_value(rast, st_GeomFromText('POINT(30.424 -1.978)', 4326))
FROM mytable;
Both subqueries appear to be unnecessary.
If you truly needed the subquery you'd write something syntactically like:
WITH sq(rast) AS ( SELECT rast FROM mytable )
SELECT st_value(rast, st_GeomFromText('POINT(30.424 -1.978)', 4326))
FROM sq;
or
SELECT st_value(rast, st_GeomFromText('POINT(30.424 -1.978)', 4326))
FROM (SELECT rast FROM mytable) sq(rast);
Try:
Select st_value(rast),
st_GeomFromText('POINT(30.424 -1.978)', 4326)
from mytable
If you have a function with multiple columns, you can do something like this
SELECT (info).column1, (info).column2, (info).column3
FROM (select st_value(rast, st_GeomFromText('POINT(30.424 -1.978)', 4326)) AS info
FROM mytable
) AS foo