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In this chapter, we will discuss how to create and execute queries on Presto. Let us go through Presto supported basic data types.
Basic Data Types
The following table describes the basic data types of Presto.
| S.No | Data type & Description |
|---|---|
| 1. |
VARCHAR Variable length character data |
| 2. |
BIGINT A 64-bit signed integer |
| 3. |
DOUBLE A 64-bit floating point double precision value |
| 4. |
DECIMAL A fixed precision decimal number. For example DECIMAL(10,3) – 10 is precision, i.e. total number of digits and 3 is scale value represented as fractional point. Scale is optional and default value is 0 |
| 5. |
BOOLEAN Boolean values true and false |
| 6. |
VARBINARY Variable length binary data |
| 7. |
JSON JSON data |
| 8. |
DATE Date data type represented as year-month-day |
| 9. |
TIME, TIMESTAMP, TIMESTAMP with TIME ZONE TIME – Time of the day (hour-min-sec-millisecond) TIMESTAMP – Date and time of the day TIMESTAMP with TIME ZONE – Date and time of the day with time zone from the value |
| 10. |
INTERVAL Stretch or extend date and time data types |
| 11. |
ARRAY Array of the given component type. For example, ARRAY[5,7] |
| 12. |
MAP Map between the given component types. For example, MAP(ARRAY[‘one’,’two’],ARRAY[5,7]) |
| 13. |
ROW Row structure made up of named fields |
Presto − Operators
Presto operators are listed in the following table.
| S.No | Operator & Description |
|---|---|
| 1. | Arithmetic operator
Presto supports arithmetic operators such as +, -, *, /, % |
| 2. | Relational operator
<,>,<=,>=,=,<> |
| 3. | Logical operator
AND, OR, NOT |
| 4. | Range operator
Range operator is used to test the value in a specific range. Presto supports BETWEEN, IS NULL, IS NOT NULL, GREATEST and LEAST |
| 5. | Decimal operator
Binary arithmetic decimal operator performs binary arithmetic operation for decimal type Unary decimal operator − The – operator performs negation |
| 6. | String operator
The ‘||’ operator performs string concatenation |
| 7. | Date and time operator
Performs arithmetic addition and subtraction operations on date and time data types |
| 8. | Array operator
Subscript operator[] – access an element of an array Concatenation operator || – concatenate an array with an array or an element of the same type |
| 9. | Map operator
Map subscript operator [] – retrieve the value corresponding to a given key from a map |
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