Grouping optional Y value data
You group Y values for different reasons, depending on the chart type, as described in Table 12‑3.
Table 12‑3 Using optional Y grouping for different chart types
Chart type
Reason for using optional Y grouping
Bar, cone, line, pyramid, tube
To summarize data into multiple sets of risers in the chart
Area, difference
To summarize data into multiple areas in the chart
Bubble
To identify bubbles using the legend
Meter
To plot multiple meters
Alternate meter subtype
To plot multiple dials
Pie
To plot multiple pies
Scatter
To plot multiple (x-y) value pairs
Stock
To plot multiple sets of candlesticks
To group y-axis values, you use Optional Y Grouping in the Select Data page of the chart builder.
Grouping Y values in a bar chart
The chart shown in Figure 12‑14 groups Y values to plot multiple sets of bars representing the monthly sum of orders for three types of vehicles.
Figure 12‑14 Bar chart that plots multiple sets of bars by grouping
Figure 12‑15 shows the axes and grouping definitions used to create this chart.
Figure 12‑15 Axes and grouping definitions for plotting multiple sets of bars
Build the expressions shown in Table 12‑4 by dragging columns from the data preview and dropping them in the three areas shown in Figure 12‑15.
Table 12‑4 Definitions of series in bar chart that uses grouping
Series
Expression
Value (Y) Series
row["QUANTITYORDERED"]
Category (X) Series
row["ORDERDATE"]
Optional Y Series Grouping
row["PRODUCTLINE"]
Grouping multiple y-axis values in a stock chart
In a stock chart, four different value series expressions provide the high, low, open, and close data. The category series expression arranges the values along the x-axis, typically along a date or time scale. To set up multiple sets of candlesticks, you can either define multiple value series definitions or use optional grouping. For example, the stock chart in Figure 12‑16 presents stock data for two companies.
Figure 12‑16 Stock chart that uses grouping
Figure 12‑17 shows the expressions used to create the chart. The chart uses the Y value expressions to set up the candlesticks and the category X expression to arrange the candlesticks in chronological order along the x‑axis. The expression, row["Symbol"], which you drag and drop in Optional Y Series Grouping, creates one set of candlesticks for each ticker symbol.
Figure 12‑17 Data expressions for the stock chart
The data for the chart is shown in Table 12‑5.
Table 12‑5 Data for a stock chart that uses grouping
Symbol
Date
Open
High
Low
Close
COA
6/15/2009
13.36
13.36
13.01
13.15
COB
6/15/2009
11.67
11.70
11.12
11.21
COA
6/16/2009
13.18
13.23
12.72
12.78
COB
6/16/2009
11.46
11.62
10.77
10.90
COA
6/17/2009
12.71
12.73
12.14
12.25
COB
6/17/2009
10.80
10.85
10.25
10.49
COA
6/18/2009
12.19
12.19
11.46
11.97
COB
6/18/2009
10.63
11.06
10.37
10.78
COA
6/19/2009
12.13
12.27
11.93
12.10
COB
6/19/2009
11.14
11.25
10.94
11.00
You can also use multiple sets of value series expressions to create multiple sets of candlesticks. For example, you can create the same chart using joined data. Table 12‑6 contains the data for company COA stocks.
Table 12‑6 Data for a stock chart using two sets of value series expressions
Date
COAOpen
COAHigh
COALow
COAClose
6/15/2009
13.36
13.36
13.01
13.15
6/16/2009
13.18
13.23
12.72
12.78
6/17/2009
12.71
12.73
12.14
12.25
6/18/2009
12.19
12.19
11.46
11.97
6/19/2009
12.13
12.27
11.93
12.10
Table 12‑7 contains the data for company COB stocks used by the same chart.
Table 12‑7 Data for the second series for a stock chart using two sets of value series expressions 
Date
COBOpen
COBHigh
COBLow
COBClose
6/15/2009
11.67
11.70
11.12
11.21
6/16/2009
11.46
11.62
10.77
10.90
6/17/2009
10.80
10.85
10.25
10.49
6/18/2009
10.63
11.06
10.37
10.78
6/19/2009
11.14
11.25
10.94
11.00
To define multiple sets of candlesticks, you use the value series drop-down list. Select New Series, shown in Figure 12‑18, and then either drag and drop columns from Chart Preview to the expression fields, or type code to create the series expressions. After you add one or more sets of expressions, you can use the drop-down list to navigate among them.
Figure 12‑18 Adding a stock chart value series
To create multiple sets of candlesticks, you use the following expressions to define the category and value series in the stock chart:
*The Category Series Definition is row["Date"].
*The first set of value series expressions uses row["COAHigh"], row["COALow"], row["COAOpen"], and row["COAClose"].
*The second set of value series expressions uses row["COBHigh"], row["COBLow"], row["COBOpen"], and row["COBClose"].