小编Kar*_*loh的帖子

我有下表:

select * from top3art;

            path             | count
-----------------------------+--------
 /article/candidate-is-jerk  | 338647
 /article/bears-love-berries | 253801
 /article/bad-things-gone    | 170098

我想在路径值中删除'/ article /',所以我这样做:

select *, trim(leading '/article/' from path) from top3art;

            path             | count  |       ltrim
-----------------------------+--------+--------------------
 /article/candidate-is-jerk  | 338647 | ndidate-is-jerk
 /article/bears-love-berries | 253801 | bears-love-berries
 /article/bad-things-gone    | 170098 | bad-things-gone

第2行和第3行工作正常.但是第一排发生了什么？它修剪了'/ article/ca'.为什么还需要2个字符？

现在看看当我修剪'/ articl'时会发生什么:

select *, trim(leading '/articl' from path) as test from top3art;

            path             | count  |         test
-----------------------------+--------+----------------------
 /article/candidate-is-jerk  | 338647 | e/candidate-is-jerk
 /article/bears-love-berries | 253801 | e/bears-love-berries …