问题
I'm trying to replace the first instance of a NULl or ' ' value in a column with another value. But only the first instance and nothing else.
So far I've put this together:
UPDATE table_name SET column = CONCAT(REPLACE(LEFT(column , INSTR(column , '')), '', 'new_value'), SUBSTRING(column , INSTR(column , '') +1))
I could replace all the values but I don't want that:
UPDATE table_name SET column = REPLACE (column , 'old_value', 'new_value')
回答1:
Just try using limit 1
UPDATE table_name SET column='new_value' WHERE column='' limit 1
来源：https://stackoverflow.com/questions/20034103/replace-first-instance-null-or-with-another-value-mysql