# Aggregating Data - MapInfo_Pro - 2023

## MapInfo Pro Help

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MapInfo
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MapInfo > MapInfo Pro
Version
2023
Language
English
Product name
MapInfo Pro
Title
MapInfo Pro Help
First publish date
1985
ft:lastEdition
2023-09-12
ft:lastPublication
2023-09-12T16:39:16.995549

When you aggregate data, you perform a mathematical operation on all of a column's values in all of the records in your table. Unlike the Select command, which only allows you to perform mathematical functions on individual records, SQL allows you to aggregate (or summarize) data across records.

MapInfo Pro looks for each unique set of data values in the specified column or columns and creates one row for each such unique set. When you aggregate data, you need to specify:

• How the records will be grouped.
• How the data will be aggregated (summarized).

For example, you have a table of sales representatives and their sales figures for the past three months:

SALES_REP MONTH SALES

John

May

1200

Cathy

May

900

Julie

May

1100

John

June

900

Cathy

June

1400

Julie

June

600

John

July

1200

Cathy

July

700

Julie

July

1000

MapInfo Pro could also compute the total sales for each representative by specifying in the SQL Select dialog box:

• Select Columns: SALES_REP, sum(SALES)
• Group by Columns: SALES_REP
SALES_REP sum(SALES)

John

3300

Cathy

3000

Julie

2700

or MapInfo Pro could compute the average sales for each representative:

• Select Columns: SALES_REP, avg(SALES)
• Group by Columns: SALES_REP
SALES_REP avg(SALES)

John

1100

Cathy

1000

Julie

900

or MapInfo Pro could compute the total sales for each month:

• Select Columns: MONTH, sum(SALES)
• Group by Columns: MONTH
MONTH sum(SALES)

May

3200

June

2900

July

2900

MapInfo Pro has six aggregate functions:

• Count(*): counts the number of records in a group. It takes * as its argument because it applies to the record as a whole, and not to any particular field in the record.
• Sum (expression): calculates the sum of the values in <expression> for all group records.
• Average (expression): calculates the average of the values in <expression> for all the records in a group.
• WtAvg (expression): calculates the weighted average of the values in <expression> for all the records in a group.
• Max (expression): finds the highest value in <expression> for all records in a group.
• Min (expression): finds the lowest value in <expression> for all records in a group.