Overview

1. Syntax Overview

SELECT ⟨select_list⟩
    FROM ⟨tables⟩
    [WHERE ⟨condition⟩]
    [GROUP BY ⟨groups⟩]
    [HAVING ⟨group_filter⟩]
    [FILL ⟨fill_methods⟩]
    [ORDER BY ⟨order_expression⟩]
    [OFFSET ⟨n⟩]
    [LIMIT ⟨n⟩];

The IoTDB table model query syntax supports the following clauses:

• SELECT Clause: Specifies the columns to be included in the result. Details: SELECT Clause
• FROM Clause: Indicates the data source for the query, which can be a single table, multiple tables joined using the JOIN clause, or a subquery. Details: FROM & JOIN Clause
• WHERE Clause: Filters rows based on specific conditions. Logically executed immediately after the FROM clause. Details: WHERE Clause
• GROUP BY Clause: Used for aggregating data, specifying the columns for grouping. Details: GROUP BY Clause
• HAVING Clause: Applied after the GROUP BY clause to filter grouped data, similar to WHERE but operates after grouping. Details:HAVING Clause
• FILL Clause: Handles missing values in query results by specifying fill methods (e.g., previous non-null value or linear interpolation) for better visualization and analysis. Details:FILL Clause
• ORDER BY Clause: Sorts query results in ascending (ASC) or descending (DESC) order, with optional handling for null values (NULLS FIRST or NULLS LAST). Details: ORDER BY Clause
• OFFSET Clause: Specifies the starting position for the query result, skipping the first OFFSET rows. Often used with the LIMIT clause. Details: LIMIT and OFFSET Clause
• LIMIT Clause: Limits the number of rows in the query result. Typically used in conjunction with the OFFSET clause for pagination. Details: LIMIT and OFFSET Clause

2. Clause Execution Order