EnSQL supports a subset of standard operators that are defined in SQL:1999. Operators include comparison operators and logical/boolean operators.
Comparison Operators
Comparison operators are used to evaluate an expression that is composed of a left-side (e.g. a in the examples below), the operator, and the right-side (e.g. b in the examples below). These operators are typically used in the WHERE clause of a query for filtering results returned in an Ensign stream.
| Operator | Syntax | Description |
|---|---|---|
= | a = b | a is equal to b |
!= | a != b | a is not equal to b |
<> | a <> b | a is not equal to b (alternate) |
> | a > b | a is greater than b |
>= | a >= b | a is greater than or equal to b |
< | a < b | a is less than b |
<= | a <= b | a is less than or equal to b |
like | a like 'pattern' | The pattern 'pattern' is found in a |
ilike | a ilike 'pattern' | Case-insensitive like search |
Logical/Boolean Operators
Logical operators return the result of a Boolean operation on an input expression that is composed of a left-side (e.g. a in the examples below), the operator, and the right-side (e.g. b in the examples below). Both input expressions on the left and ride side must evaluate to a boolean value.
Logical operators can only be used as a predicate/condition e.g. in the WHERE clause of a SQL statement.
| Operator | Syntax | Description |
|---|---|---|
AND | a AND b | Both a and b must evaluate to true to be true otherwise false |
OR | a OR b | Either a or b must evaluate to true to be true otherwise false |
The order of precedence of these operators is shown below from highest to lowest:
- AND
- OR
NOTE: When we add the NOT logical operator in the future, it will have the highest precedence.
