Operators in [Druid SQL](./sql.md) typically operate on one or two values and return a result based on the values. Types of operators in Druid SQL include arithmetic, comparison, logical, and more, as described here.
When performing math operations, Druid uses 64-bit integer (long) data type unless there are double or float values. If an operation uses float or double values, then the result is a double, which is a 64-bit float. The precision of float and double values is defined by [Java](https://docs.oracle.com/javase/specs/jls/se8/html/jls-5.html) and [the IEEE standard](https://en.wikipedia.org/wiki/IEEE_754).
Keep the following guidelines in mind to help you manage precision issues:
- Long values can store up to 2^63 accurately with an additional bit used for the sign.
- Float values use 32 bits, and doubles use 64 bits. Both types are impacted by floating point precision. If you need exact decimal values, consider storing the number in a non-decimal format as a long value (up to the limit for longs). For example, if you need three decimal places, store the number multiplied by 1000 and then divide by 1000 when querying.
For the datetime arithmetic operators, `interval_expr` can include interval literals like `INTERVAL '2' HOUR`.
This operator treats days as uniformly 86400 seconds long, and does not take into account daylight savings time.
To account for daylight savings time, use the [`TIME_SHIFT` function](sql-scalar.md#date-and-time-functions).
Also see [`TIMESTAMPADD`](sql-scalar.md#date-and-time-functions) for datetime arithmetic.
|Operator|Description|
|--------|-----------|
|`timestamp_expr + interval_expr`|Add an amount of time to a timestamp.|
|`timestamp_expr - interval_expr`|Subtract an amount of time from a timestamp.|
## Concatenation operator
Also see the [CONCAT function](sql-scalar.md#string-functions).
|Operator|Description|
|--------|-----------|
|<code>x || y</code>|Concatenate strings `x` and `y`.|
## Comparison operators
|Operator|Description|
|--------|-----------|
|`x = y` |Equal to|
|`x <> y`|Not equal to|
|`x > y` |Greater than|
|`x >= y`|Greater than or equal to|
|`x <y`|Lessthan|
|`x <= y`|Less than or equal to|
## Logical operators
|Operator|Description|
|--------|-----------|
|`x AND y`|Boolean AND|
|`x OR y`|Boolean OR|
|`NOT x`|Boolean NOT|
|`x IS NULL`|True if _x_ is NULL or empty string|
|`x IS NOT NULL`|True if _x_ is neither NULL nor empty string|
|`x IS TRUE`|True if _x_ is true|
|`x IS NOT TRUE`|True if _x_ is not true|
|`x IS FALSE`|True if _x_ is false|
|`x IS NOT FALSE`|True if _x_ is not false|
|`x BETWEEN y AND z`|Equivalent to `x >= y AND x <= z`|
|`x NOT BETWEEN y AND z`|Equivalent to `x < y OR x > z`|
|`x LIKE pattern [ESCAPE esc]`|True if _x_ matches a SQL LIKE pattern (with an optional escape)|
|`x NOT LIKE pattern [ESCAPE esc]`|True if _x_ does not match a SQL LIKE pattern (with an optional escape)|
|`x IN (values)`|True if _x_ is one of the listed values|
|`x NOT IN (values)`|True if _x_ is not one of the listed values|
|`x IN (subquery)`|True if _x_ is returned by the subquery. This will be translated into a join; see [Query translation](sql-translation.md) for details.|
|`x NOT IN (subquery)`|True if _x_ is not returned by the subquery. This will be translated into a join; see [Query translation](sql-translation.md) for details.|