On 6/26/2018 9:15 AM, Csányi Pál wrote:
I have the 'SchoolYearTeachingDays' table with just one column, in which are dates:CREATE TABLE SchoolYearTeachingDays ( aDate DATE PRIMARY KEY UNIQUE ); I filled it with many dates which are unique. These dates excludes dates for Sundays and for Saturdays. I have another, the 'TeachingSaturdaysInSchoolYear' table: CREATE TABLE TeachingSaturdaysInSchoolYear ( id INT PRIMARY KEY UNIQUE, aDate DATE, TimetableForTheDay TEXT ); This table holds just two dates. These two dates are for two Saturdays. On these two Saturdays we have to teach students. When I do the following query on this table, I get these two records: 2018-04-14 2018-05-05 I want to INSERT these two dates from the 'TeachingSaturdaysInSchoolYear' table into 'SchoolYearTeachingDays' table. I am trying with this query: INSERT INTO SchoolYearTeachingDays SELECT aDate FROM TeachingSaturdaysInSchoolYear ; but I get this error: Error: UNIQUE constraint failed: SchoolYearTeachingDays.aDate
This means that, despite your assumption to the contrary, at least one of those two dates is already present in SchoolYearTeachingDays
Then I get help and this code: INSERT INTO SchoolYearTeachingDays SELECT aDate FROM TeachingSaturdaysInSchoolYear T WHERE T.aDate NOT IN (SELECT S.aDate FROM SchoolYearTeachingDays S)
This says "insert all dates that aren't already present", which of course avoids UNIQUE constraint.
I wish to know followings. How many times want to inserts the SELECT query the one of the date from the TeachingSaturdaysInSchoolYear table into SchoolYearTeachingDays table?
I don't understand this question.
That is: the how many times wants select statement to insert one record from first table into second table?
Each row in the resultset of SELECT statement is inserted once, of course. -- Igor Tandetnik _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
