如何在PostgreSQL中替换文本列中的字符数组? [英] How to replace an array of characters in a column of text in PostgreSQL?

问题描述

我有2个文本列，需要在更新时将数组1中的字符("q"，"x"，"y"，"z")替换为数组2中的索引等效值("a")'，'b'，'c'，'d').

I have 2 text columns where I need to replace (on update) chars from array 1 ('q','x','y','z') to their index-equivalent value in array 2 ('a','b','c','d').

我最接近atm的是这样将替换调用相互嵌套在一起<​​/p>

The closest I've come to atm is to nest the replace calls within each other like so

UPDATE 
    mytable 
SET 
    col1=replace(
            replace(
                replace(
                    replace(
                        col1,'q','a'
                    ),'x','b'
                ),'y','c'
            ),'z','d'
        ),
    col2=replace(
            replace(
                replace(
                    replace(
                        col2,'q','a'
                    ),'x','b'
                ),'y','c'
            ),'z','d'
        )        

但是肯定有更好的方法可以做到这一点吗?在我的实际情况下，我有14个字符对.如果有相关性，这些字符是日本象形文字和瑞典字母的带重音字母的组合.

but surely there must be a better way to do this? In my live case I have 14 of those char pairs. If it has any relevance - the chars are a mix of japanese hieroglyphs and accented letters from Swedish alphabet.

推荐答案

PostgreSQL为此具有特殊功能，

PostgreSQL have special function for this, translate():

update mytable set
    col1 = translate(col1, 'qxyz', 'abcd'),
    col2 = translate(col2, 'qxyz', 'abcd')

sql小提琴示例

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