When the data type of a column is VARCHAR, you do not need to know how many blanks to specify with LIKE. With VARCHAR, there are no blanks in the column. The size of the column varies with the size of its data.
When the data type of a column is CHAR, however, the size of the column is fixed. The column contains blanks, so use the appropriate number of blanks when you specify LIKE.
If the data type of a column is LONG VARCHAR or LONG VARGRAPHIC, you cannot use it with LIKE (or any other search conditions).