like/LIKE
like/LIKE is a logical operator that is used to retrieve the data in a column of a table, based on a specified pattern. It is equivalent to function like.
Syntax
match_expression [NOT] LIKE pattern
match_expression is a column name or an expression containing column name.
pattern is a string (case sensitive) to be searched in match_expression. The following wildcards can be used:
% represents zero, one or multiple characters.
? represents one character.
If match_expression matches pattern, it returns true, otherwise returns false. If “not” is specified, an opposite result is returned. The like keyword is usually used in a where clause to filter data based on a specific pattern. For example, to select data that starts with “A”, ends with “B”, or contains “Ca”.
Examples
$ t= table(`a1`a2`a3`b1`b2`b3`c1`c2 as id, 7 4 NULL 1 8 NULL 12 NULL as val)
$ select * from t where id like "a%"
//equivalent to select * from t where like(id, "a%")
id |
val |
|---|---|
a1 |
7 |
a2 |
4 |
a3 |
$ select * from t where id not like "a%"
id |
val |
|---|---|
b1 |
1 |
b2 |
8 |
b3 |
|
c1 |
12 |
c2 |