只包含空格的 select * from tbname where trim(colname) is null;
ORACLE不管什么字段类型,在SQL语句判断NULL都是colname is null或colname is not null
select * from tbname where trim(colname) is null;这应该是包含那些是NULL的记录和包含有若干空格的的记录
select * from table where Trim(colname) is null; select * from table where Trim(colname) is not null; select * from table where Trim(colname)=''; select * from table where Trim(colname) is nothing;
select * from tbname where colname is null select * from tbname where colname is not null
select * from tbname where trim(colname) is null;
select * from table where Trim(colname) is not null;
select * from table where Trim(colname)='';
select * from table where Trim(colname) is nothing;
select * from tbname where colname is not null