Changing data types
by Matt Floyd, Ashley Ohmann, Ashutosh Nandeshwar, Jen Stirrup
Tableau: Creating Interactive Data Visualizations
- Tableau: Creating Interactive Data Visualizations
- Table of Contents
- Tableau: Creating Interactive Data Visualizations
- Tableau: Creating Interactive Data Visualizations
- Credits
- Preface
- 1. Module 1
- 1. A Short Dash to Dashboarding!
- 2. Summarizing Your Data for Dashboards
- 3. Interacting with Data for Dashboards
- 4. Using Dashboards to Get Results
- 5. Putting the Dash into Dashboards
- 6. Making Dashboards Relevant
- 7. Visual Best Practices
- 2. Module 2
- 1. Connecting to Data Sources
- Introduction
- Connecting to text files
- Connecting to Excel files
- Connecting to Access databases
- Connecting to a SQL Server
- Pasting from a clipboard
- Connecting to other databases
- Connecting to Windows Azure Marketplace
- Understanding dimensions and measures
- Changing data types
- Applying filters
- Merging multiple data sources
- 2. Creating Univariate Charts
- 3. Creating Bivariate Charts
- 4. Creating Multivariate Charts
- 5. Creating Maps
- 6. Calculating User-defined Fields
- 7. Customizing and Saving
- 8. Exporting and Sharing
- 9. Exploring Advanced Features
- 1. Connecting to Data Sources
- 3. Module 3
- 1. Getting Started with Tableau Public
- 2. Tableau Public Interface Features
- 3. Connecting to Data
- 4. Visualization – Tips and Types
- 5. Calculations
- 6. Level of Detail and Table Calculations
- 7. Dashboard Design and Styling
- 8. Filters and Actions
- 9. Publishing Your Work
- A. Bibliography
- Index
Depending on the data source and connection, Tableau tries to determine the field data type. Most often, the field data types are identified correctly; sometimes, however, changing data types becomes necessary.
We will use the sample superstore sales saved data source for this exercise. Open a new worksheet and connect to the Sample – Superstore Sales (Excel) data source.
Once the sample file is loaded on the worksheet, perform the following steps to convert data types:
- In the Dimensions pane, right-click on Order Date.
- You'll notice some data types in Tableau: Number, String, and Date. Date & time is also a type, which is suited for data with a timestamp.
- Select String as the data type for this field. Next to this field name, you'll notice a symbol with letters (Abc); this symbol indicates that this field contains data of type String.
- Drag the Order Date field from the Dimensions to the Measures pane.
- You'll notice in the Measures pane that the field Order Date has an aggregation of Count.
- Right-click on Order Date (Count) in the Measures pane and select Change Data Type. Select Date as the new data type.
- You'll notice that the Order Date field is back in the Dimensions pane.
Since the data type and role of a field (dimension or measure) determines how the data will be used in the visualizations, it is critical to have the right data type for fields in the data. You will notice that, if you convert a field in the Measures pane to a Date type, that field will be moved to Dimensions. If a field from the Dimensions pane is converted to Number, it will stay in the Dimensions pane. If a field from the Measures pane is converted to String, the default aggregation changes to Count.
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