Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Your title mentions "merge" but you seem to have not tried the <code>merge</code> function. (Or am I missing something?)</p> <p>Here are your first two example <code>data.frame</code>s:</p> <pre><code>DF1 &lt;- structure(list(T1 = c("T2", "T1", "T2", "T1", "T2", "T1", "T2" ), A1 = c("A1", "A2", "A2", "A1", "A1", "A2", "A2"), B1 = c("B1", "B1", "B1", "B2", "B2", "B2", "B2")), .Names = c("T1", "A1", "B1"), class = "data.frame", row.names = c(NA, -7L)) DF2 &lt;- structure(list(T1 = c("T1", "T2", "T1", "T2", "T2", "T2"), A2 = c("A2", "A2", "A1", "A1", "A2", "A1"), B2 = c("B1", "B1", "B1", "B2", "B2", "B1"), X1 = c(3L, 3L, 1L, 2L, 2L, 2L)), .Names = c("T1", "A2", "B2", "X1"), class = "data.frame", row.names = c(NA, -6L)) </code></pre> <p>Here's how you use <code>merge</code> from base R. The <code>by.x</code> and <code>by.y</code> arguments should include the names of the columns that you should have in common in both <code>data.frame</code>s. The <code>all</code> argument says to not drop any "blanks" but fill them with <code>NA</code> instead.</p> <pre><code>merge(DF1, DF2, by.x = c("T1", "A1", "B1"), by.y = c("T1", "A2", "B2"), all = TRUE) # T1 A1 B1 X1 # 1 T1 A1 B1 1 # 2 T1 A1 B2 NA # 3 T1 A2 B1 3 # 4 T1 A2 B2 NA # 5 T2 A1 B1 2 # 6 T2 A1 B2 2 # 7 T2 A2 B1 3 # 8 T2 A2 B2 2 </code></pre> <p>Here's the result of <code>merge</code> on the two <code>data.frame</code>s that Arun created. Notice that we don't need to specify which columns to merge on since they have common column names.</p> <pre><code>merge(df1, df2, all = TRUE) # V1 V2 V3 run.no run.no.std.rp Block.ccd A B C D # 1 T1 A1 B1 4 C0.3 0 450 120.0 8 4.000 # 2 T1 A1 B2 NA &lt;NA&gt; NA NA NA NA NA # 3 T1 A2 B1 2 C0.7 0 450 120.0 2 4.000 # 4 T1 A2 B2 1 C0.17 0 400 147.5 5 2.675 # 5 T2 A1 B1 7 C0.15 0 450 120.0 2 1.350 # 6 T2 A1 B2 5 C0.4 0 350 120.0 8 4.000 # 7 T2 A2 B1 3 C0.6 0 350 175.0 2 4.000 # 8 T2 A2 B2 6 C0.16 0 350 120.0 2 1.350 </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POLogical Merging of Dataframes
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USA5C1D2H2I1M1N2O1R2T1
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POLogical Merging of Dataframes
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    1. COWill try this and report back, @anada
      singulars
      1. PO
      1. USuser1945827
    2. COBoth answers work on the example data given. Thanks for your help. I ticked both answers but the default settings only allow one answer to prevail. Particular thanks to @Arun for drawing my attention to data.tables.
      singulars
      1. PO
      1. USuser1945827
    3. COWhen applied to my real data set I got 'Error in fix.by(by.x, x) : 'by' must match numbers of columns' Here's my attempt, attempt.1 <- merge(core.structure, core.results, by.x = c(core.structure$6, core.structure$7, core.structure$8, core.structure$9), by.y = c(core.results[,2], core.results[,3], core.results[,6], core.results[,4]), all = TRUE). My unique patterns in the first DF are in columns 6,7,8, 9 while they are in columns 2,3,6,4 for my second DF.
      singulars
      1. PO
      1. USuser1945827
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload