如何在psql的命令行查詢中轉義單引號？

Question

我GOOGLE了很多，但..

如何在psql的命令行查詢中轉義單引號？

psql -t -A -F $'\t' postgresql://zzzz:5432/casedb -U qqqq -c 'select id,ext_ids ->> 'qwe' as qwe from data ORDER BY qwe' > /jdata/qwe.tab 

結果在誤差

ERROR: column "qwe" does not exist 
LINE 1: select id,ext_ids ->> qwe as qwe from data... 

Answer 1

在Postgres裏你可以使用dollar-quoted strings：

select id,ext_ids ->> $$qwe$$ as qwe from data ORDER BY qwe; 
-- or 
select id,ext_ids ->> $anything$qwe$anything$ as qwe from data ORDER BY qwe; 

Answer 2

你可以只使用了殼報價爲SQL雙引號（"）和單引號（'）報價：

psql -t -A -F $'\t' postgresql://zzzz:5432/casedb -U qqqq -c "select id,ext_ids ->> 'qwe' as qwe from data ORDER BY qwe" > /jdata/qwe.tab 
# Here ------------------------------------------------------^---------------------------------------------------------^