Does the R function sqldf() support a way to show table columns similar to what the sql command "desc my_table" would do. It does not seem to support "desc my_table" or "describe_my_table" and I'm not seeing a way to do this in the documentation at the links below:
https://www.rdocumentation.org/packages/sqldf/versions/0.4-11
https://www.rdocumentation.org/packages/sqldf/versions/0.4-11/topics/sqldf
install.packages("sqldf")
> data_file <- "path/to/file/dash-activity.csv"
> data <- read.csv(data_file)
> sqldf("
select
state,
count(*) as count,
round(cast(count(*) as real)/154 * 100, 2) as pct
from data
group by 1
order by 1
")
state count pct
1 DE 12 7.79
2 FL 18 11.69
3 HI 23 14.94
4 KY 5 3.25
5 MD 31 20.13
6 ME 4 2.60
7 NC 7 4.55
8 ND 4 2.60
9 NM 13 8.44
10 NV 4 2.60
11 RI 5 3.25
12 VA 9 5.84
13 VT 13 8.44
14 WV 6 3.90
> sqldf("
desc data
")
Error: near "desc": syntax error
> sqldf("
describe data
")
Error: near "describe": syntax error
>
--- EDIT -----------------------
The accepted answer gives the following results (my table is named "data")
> sqldf("pragma table_info('data')")
cid name type notnull dflt_value pk
1 0 sex TEXT 0 NA 0
2 1 race TEXT 0 NA 0
3 2 grade TEXT 0 NA 0
4 3 location_id INTEGER 0 NA 0
5 4 state TEXT 0 NA 0
6 5 location_desc TEXT 0 NA 0
7 6 short_question TEXT 0 NA 0
8 7 greater_risk_question TEXT 0 NA 0
9 8 pct_were_not_active REAL 0 NA 0
10 9 units TEXT 0 NA 0
CodePudding user response：
Using pragma:
library(sqldf)
d <- head(iris[ c(1,5) ])
sqldf("select * from d")
sqldf("pragma table_info('d')")
# cid name type notnull dflt_value pk
# 1 0 Sepal.Length REAL 0 NA 0
# 2 1 Species TEXT 0 NA 0