Query q = sessionFactory.getCurrentSession().createQuery(“from LoginInfo where userName = :name”); q.setParameter(“name”, userName); List<LoginInfo> loginList = q.list(); You have other options too, see this nice article from mkyong.
You could: SELECT COALESCE(SUM(columnA), 0) FROM my_table WHERE columnB = 1 INTO res; This happens to work, because your query has an aggregate function and consequently always returns a row, even if nothing is found in the underlying table. Plain queries without aggregate would return no row in such a case. COALESCE would never be … Read more
Try this SELECT Count(*) AS N FROM (SELECT DISTINCT Name FROM table1) AS T; Read this for more info.
It was actually a mistake from my part… the answer to my first question lies in that query itself. I just have to enclose the (array_agg(team_name))[1], earlier I tried it without the brackets. SELECT team_id, (array_agg(team_name))[1] AS teamname, array_agg(player_id||’##’||player_name) AS playerdetails FROM team INNER JOIN players ON team_id = player_team GROUP BY team_id
Find the first character that is not CHAR(13) or CHAR(10) and subtract its position from the string’s length. LTRIM() SELECT RIGHT(@MyString,LEN(@MyString)-PATINDEX(‘%[^’+CHAR(13)+CHAR(10)+’]%’,@MyString)+1) RTRIM() SELECT LEFT(@MyString,LEN(@MyString)-PATINDEX(‘%[^’+CHAR(13)+CHAR(10)+’]%’,REVERSE(@MyString))+1)
When you imported this “Northwind” database column names were imported in CamelCase – your import must’ve added double quotes to column identifiers to create table queries. This is rather unfortunate, as this would cause that you’d have to quote them also in all queries, like: select “City” from customers; To remain sane I’d suggest you … Read more
While my original answer gave a working solution, I was actually wrong about the cause of the error. There is nothing wrong with using a scalar subquery inside a VALUES clause. The problem with the statement in the question is simply that one parenthesis is in the wrong place; the scalar subquery must be enclosed … Read more
One index on a table is not a big deal. You automatically have an index on columns (or combinations of columns) that are primary keys or declared as unique. There is some overhead to an index. The index itself occupies space on disk and memory (when used). So, if space or memory are issues then … Read more
It’s the recurring problem of SELECT or INSERT under possible concurrent write load, related to (but different from) UPSERT (which is INSERT or UPDATE). This PL/pgSQL function uses UPSERT (INSERT … ON CONFLICT ..) to INSERT or SELECT a single row: CREATE OR REPLACE FUNCTION f_tag_id(_tag text, OUT _tag_id int) LANGUAGE plpgsql AS $func$ BEGIN … Read more