I am trying to find if a certain column requires TRIM
function on it.
How can I find out if this column in a table has records that have white space either before or after the actual data.
You can check it using the TRIM
function itself, not the most efficient but accurate:
Select *
From TableA
Where MyColumn <> TRIM(MyColumn)
Though if you're checking then turning around to trim anyway, you probably want to just do it in the first place, like this:
Select TRIM(MyColumn) as TrimmedMyColumn
From TableA
快速而肮脏的方式
WHERE LENGTH(TRIM(COL1)) <> LENGTH(COL1)
You could use regular expressions in Oracle.
Example:
select * from your_table
where regexp_like(your_column, '^[ ]+.*')
or regexp_like(your_column, '.*[ ]+$')
So why can't you use the following to find the leading spaces? I've been able to identify the records with leading spaces this way and using '% ' to find the trailing spaces.
SELECT mycolumn
FROM my_table
WHERE mycolumn LIKE ' %'
I've also used the following to remove both the leading and trailing spaces
Update My_table set Mycolumn = TRIM(Mycolumn)
which seems to work just fine.
select data1, length(data1)-length(replace(data1,' ','')) from t;
如果其中一个表字段T $ DSCA在末尾有尾随空格,则查询将检索行:SELECT * from TABLE_NAME A WHERE RAWTOHEX(SUBSTR(AT $ DSCA,LENGTH(T $ DSCA),1))='A0'和TRIM (T $ DSCA)不为空;
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