如何在psql的命令行查询中转义单引号？

Question

我GOOGLE了很多，但..

如何在psql的命令行查询中转义单引号？

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 

结果在误差

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

Answer 1

在Postgres里你可以使用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

你可以只使用了壳报价为SQL双引号（"）和单引号（'）报价：

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 ------------------------------------------------------^---------------------------------------------------------^