在PostgreSQL中串联

Question

我有一个宽度和高度（均为整数）的表。我想按原样显示它。例如：width = 300 and height =160。Area = 300 x160。我正在使用以下查询

  select cast(concat(width,'x',height) as varchar(20)) from table;

要么

select concat(width,'x',height) from table;

但我收到以下错误。

ERROR: function concat(character varying, "unknown", character varying) does not exist

Hint: No function matches the given name and argument types. You may need to add explicit type casts.

谁能告诉我该怎么做？谢谢

Answer 1

按以下方式使用||：https : //www.postgresql.org/docs/current/static/functions-string.html

select width || 'x' || height from table;

小提琴示例：http ://sqlfiddle.com/#!15/ f10eb/1/0