Question

我正在尝试使用Bash在我的postgres db上构建查询。我有一个asnums数组，我想查询数据库中的表（dcan_nodup）（ixmaps），以计算这些asnum出现的行数。

以下代码段正常工作，其下方没有。

WORKS（使用期望值生成逗号分隔的csv）：

declare -a carriers=(6461 17025 33139 17899 7018 5730 4466 577 6549 11489)
echo ""
echo "Generating CrFreqTR..."
for asnum in "${carriers[@]}"
do
    echo $asnum
    count=$(psql -d ixmaps -Atc "select count(distinct traceroute_id) from dcan_nodup where asnum = '$asnum';")
    echo $count
    echo $asnum", "$count >> dcan_crfreq_tr.csv
done

不工作：

declare -a whereConditions=('asnum = 6461 or asnum = 17025' 'asnum = 33139' 'asnum = 17899' 'asnum = 7018 or asnum = 5730 or asnum = 4466' 'asnum = 577 or asnum = 6549 or asnum = 11489')
for w in "${whereConditions[@]}"
do
    echo $w

    echo psql -d ixmaps -Atc "select count(distinct traceroute_id) from dcan_nodup where "$w";"
    psql -d ixmaps -Atc "select count(distinct traceroute_id) from dcan_nodup where "$w";"
    echo "NOPE #1"

    count=$(psql -d ixmaps -Atc "select count(distinct traceroute_id) from dcan_nodup where '$w';")
    echo $count
    echo "NOPE #2"
    echo $w", "$count >> dcan_crfreq_tr.csv
done

NOPE＃1结果：

asnum = 6461 or asnum = 17025
psql -d ixmaps -Atc select count(distinct traceroute_id) from dcan_nodup where asnum = 6461 or asnum = 17025;
psql: warning: extra command-line argument "6461" ignored
psql: warning: extra command-line argument "or" ignored
psql: warning: extra command-line argument "asnum" ignored
psql: warning: extra command-line argument "=" ignored
psql: warning: extra command-line argument "17025;" ignored
psql: FATAL:  Ident authentication failed for user "="
NOPE #1
asnum = 33139
psql -d ixmaps -Atc select count(distinct traceroute_id) from dcan_nodup where asnum = 33139;
psql: warning: extra command-line argument "33139;" ignored
psql: FATAL:  Ident authentication failed for user "="
NOPE #1
asnum = 17899
psql -d ixmaps -Atc select count(distinct traceroute_id) from dcan_nodup where asnum = 17899;
psql: warning: extra command-line argument "17899;" ignored
psql: FATAL:  Ident authentication failed for user "="
...

NOPE＃2结果：

asnum = 6461 or asnum = 17025
ERROR:  invalid input syntax for type boolean: "asnum = 6461 or asnum = 17025"
NOPE #2
asnum = 33139
ERROR:  invalid input syntax for type boolean: "asnum = 33139"
...

我想要做的是使用OR条件来组合两个或更多个asns的计数。如果我手动执行此操作就可以了，例如：

ixmaps@trgen:~/scripts$ psql -d ixmaps -Atc "select count(distinct traceroute_id) from dcan_nodup where asnum = 6461 or asnum = 17025;"
124

但我无法在bash循环中使其工作......

我怀疑我要么没有正确地转义变量，要么没有正确地连接字符串，或者同样简单的事情 - 我是一个bash新手...

Answer 1

当你展开$w时，你的问题很可能就是从双引号中删除。

假设w='one two'。

比较printf %s\\n "foo "$w" bar"的输出：

foo one
two bar

到printf %s\\n "foo$wbar"：

foo one two bar

所以你不想要

psql ... "select ... "$w"...;"

而不是你想要的

psql ... "select ... $w ...;"

Answer 2

像这样？

declare -a carriers=(6461 17025 33139 17899 7018 5730 4466 577 6549 11489)

function join { local IFS="$1"; shift; echo "$*"; } 

echo ""
echo "Generating CrFreqTR..."

q= "copy ( select asnum count(distinct traceroute_id) from dcan_nodup where asnum in (" \
    `join , "${carriers[@]"` ") group by asnum ) TO STDOUT WITH CSV";

 psql -d ixmaps -Atc "$q" >> dcan_crfreq_tr.csv

Bash，条件，postgres选择的数组

2 个答案: