The condition of judgment is the length of a string

Condition | string 2004-10-810:49:42 green make good use of time (f) Wingc@sql is also not simple AH Wu Cong, consult the SQL, if the condition is judged by the length of a string, such as the Column1 field length is 3, such as "001" can be selected. How to write such a condition?? I google it 2004-10-810:50:37 (f) Wingc@sql is not easy, green make good use of time in SQL Server Len (field name) = 3, have you tried? 2004-10-810:50:55 Green make good use of time (f) Wingc@sql is not simple AH no 2004-10-810:50:59 green make good use of time (f) Wingc@sql is not simple ah, I am the fact 2004-10-810:53:00 Green Make good use of your time (f) Wingc@sql is not easy. Error is on line 1th: ORA-00904: Invalid column name 2004-10-810:53:14 Green make good use of time (f) Wingc@sql is not easy to forget to say, I'm using oracle2004-10-810:53:31 to make good use of time (f) Wingc@sql is also not simple. Select * from Dt_function_node where len (node_code) = 3; 2004-10-810:54:09 (f) Wingc@sql is also not simple AH green make good use of time as if Oracle is length () 2004-10-810:54:26 (f) Wingc@sql is not easy, green Make the most of your time, and the Oracle help should be found. 2004-10-810:55:03 Green make good use of time (f) Wingc@sql is not simple ah chenggongle 2004-10-810:55:13 (f) Wingc@sql is not easy to make good use of time ok2004-10-810 : 55:17 Green make good use of time (f) Wingc@sql is not easy. Oracle Help