Geek Answers Handbook

Case expressions and aliases in jOOQ 3.5.3

I am having trouble expressing the following query in jOOQ

SELECT s.season_name, l.league_name,
  COUNT(CASE WHEN m.full_time_result = 'H' THEN 'H' END) AS home_wins,
  COUNT(CASE WHEN m.full_time_result = 'D' THEN 'D' END) AS draws,
  COUNT(CASE WHEN m.full_time_result = 'A' THEN 'A' END) AS away_wins,
  COUNT(m.full_time_result) AS all_matches
  FROM football_stats.matches AS m
  JOIN football_stats.seasons AS s USING (season_id)
  JOIN football_stats.leagues AS l USING (league_id) GROUP BY s.season_name, l.league_name

My Java code for this:

final Field<String> homeWins = DSL.decode().when(MATCHES.FULL_TIME_RESULT.eq(HOME_WIN), HOME_WIN).as("home_wins");
final Field<String> draws = DSL.decode().when(MATCHES.FULL_TIME_RESULT.eq(DRAW), DRAW).as("draws");
final Field<String> awayWins = DSL.decode().when(MATCHES.FULL_TIME_RESULT.eq(AWAY_WIN), AWAY_WIN).as("away_wins");
final Field<?>[] fields = {SEASONS.SEASON_NAME, LEAGUES.LEAGUE_NAME, DSL.count(homeWins), DSL.count(draws), DSL.count(awayWins), DSL.count()};
final SelectQuery<Record> query = dslContext.selectQuery();
query.addSelect(fields);
query.addFrom(MATCHES);
query.addJoinOnKey(SEASONS, JoinType.JOIN, Keys.MATCHES__FK_MATCHES_SEASONS);
query.addJoinOnKey(LEAGUES, JoinType.JOIN, Keys.MATCHES__FK_MATCHES_LEAGUES);
query.addGroupBy(SEASONS.SEASON_NAME,LEAGUES.LEAGUE_NAME);
final Record result = query.fetchOne();

And the query generated by jOOQ:

select 
  "football_stats"."seasons"."season_name", 
  "football_stats"."leagues"."league_name", 
  count("home_wins"), 
  count("draws"), 
  count("away_wins"), 
  count(*)
from "football_stats"."matches"
  join "football_stats"."seasons"
  on "football_stats"."matches"."season_id" = "football_stats"."seasons"."season_id"
  join "football_stats"."leagues"
  on "football_stats"."matches"."league_id" = "football_stats"."leagues"."league_id"
group by 
  "football_stats"."seasons"."season_name", 
  "football_stats"."leagues"."league_name"

it leads to

ERROR: column "home_wins" does not exist

However, when I omit .as("alias_name"), jOOQ generates

select 
  "football_stats"."seasons"."season_name", 
  "football_stats"."leagues"."league_name", 
  count(case when "football_stats"."matches"."full_time_result" = 'H' then 'H' end), 
  count(case when "football_stats"."matches"."full_time_result" = 'D' then 'D' end), 
  count(case when "football_stats"."matches"."full_time_result" = 'A' then 'A' end), 
  count(*)
from "football_stats"."matches"
  join "football_stats"."seasons"
  on "football_stats"."matches"."season_id" = "football_stats"."seasons"."season_id"
  join "football_stats"."leagues"
  on "football_stats"."matches"."league_id" = "football_stats"."leagues"."league_id"
group by 
  "football_stats"."seasons"."season_name", 
  "football_stats"."leagues"."league_name"

How can I get jOOQ to generate it like count(case when "football_stats"."matches"."full_time_result" = 'A' then 'A' end) as 'away_wins'?

Also, can I get it to generate USINGinstead ON(the addJoinUsingmethod also generates ON)?

+4
source share
1 answer

You wrote the wrong expression

In SQL, you wrote:

COUNT(CASE WHEN m.full_time_result = 'H' THEN 'H' END) AS home_wins

With jOOQ, you wrote:

homeWins = decode().when(MATCHES.FULL_TIME_RESULT.eq(HOME_WIN), HOME_WIN).as("home_wins");

and then:

DSL.count(homeWins);

So, jOOQ generates exactly the SQL that you wrote.

You intended, however, to write this:

homeWins = decode().when(MATCHES.FULL_TIME_RESULT.eq(HOME_WIN), HOME_WIN);

and then:

DSL.count(homeWins).as("home_wins");

Side Note:

jOOQ 3.6 COUNT(CASE...), SQL standard FILTER :

DSL.count().filterWhere(MATCHES.FULL_TIME_RESULT.eq(HOME_WIN)).as("home_wins")
+2

More articles:


All Articles