如何获取表中字段使用的最大大小 [英] how to get the max size used by a field in table

问题描述

我有一个已设置为最大大小的字段.我如何找到该字段占用的最大大小.

I have a field which has been set to max size. How can i find the max size occupied by the field.

例如，如果记录是表 TableA

For example if the records are for table TableA

FieldA

123
abcd
1234567

我需要知道哪一行占用的大小最多，大小是多少

I need to know which row occupied the most size and what the size is

谢谢

普拉迪

推荐答案

LEN 测试以字符为单位的长度，例如"a" = 1 个字符

LEN tests for the length in characters, e.g. "a" = 1 char

select max(len(fieldA)) from tbl

DATALENGTH 以字节为单位检查大小，一个 NVarchar 每个字符占用 2 个字节

DATALENGTH checks for the size in bytes, an NVarchar occupies 2 bytes per character

select max(datalength(fieldA)) from tbl

获取表中FieldA中数据长度最大的所有行，

To get all the rows in the table that have the maximum length of data in FieldA,

select *
from tbl join (select MAX(LEN(fieldA)) maxlen from tbl) l
    on l.maxlen = LEN(tbl.fieldA)

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