![]() ![]() ![]() Second, add a comma-separated list of columns after the table name. This will produce the following result, where there is no duplicate entry. INSERT INTO table (column1,column2 .) VALUES ( value1, value2 .) Code language: SQL (Structured Query Language) (sql) Let’s examine the INSERT statement in more detail: First, specify the name of the table to which you want to insert data after the INSERT INTO keywords. Sqlite> SELECT DISTINCT name FROM COMPANY ![]() Now, let us use DISTINCT keyword with the above SELECT query and see the result. SELECT DISTINCT column1, lumnNĬonsider COMPANY table with the following records.įirst, let us see how the following SELECT query returns duplicate salary records. If you use one column, SQLite uses values in that column to evaluate the duplicate. Second, you place a column or a list of columns after the DISTINCT keyword. Syntaxįollowing is the basic syntax of DISTINCT keyword to eliminate duplicate records. In this syntax: First, the DISTINCT clause must appear immediately after the SELECT keyword. A ' uniqueness constraint' is an explicit UNIQUE or PRIMARY KEY constraint within the CREATE TABLE statement, or a unique index. In the second step, if any constraint violation e.g., NOT NULL constraint occurs, the REPLACE statement will abort the action and. 4 Answers Sorted by: 31 Declare a unique constraint on (user, location). The main reasons that differentiate each of these methods are: The ease of applying them. The UPSERT processing happens only for uniqueness constraints. The idea of the REPLACE statement is that when a UNIQUE or PRIMARY KEY constraint violation occurs, it does the following: First, delete the existing row that causes a constraint violation. While fetching such records, it makes more sense to fetch only unique records instead of fetching duplicate records. In SQLite, there are multiple ways to avoid duplicate entries. There may be a situation when you have multiple duplicate records in a table. There is a great need for a sarcasm font.SQLite DISTINCT keyword is used in conjunction with SELECT statement to eliminate all the duplicate records and fetching only the unique records. The default conflict resolution algorithm is ABORT. There are five conflict resolution algorithm choices: ROLLBACK, ABORT, FAIL, IGNORE, and REPLACE. The ON CONFLICT algorithm does not apply to FOREIGN KEY constraints. I would assume SQLite also uses some kind of a sequence for PK The ON CONFLICT clause applies to UNIQUE, NOT NULL, CHECK, and PRIMARY KEY constraints. The DISTINCT clause allows you to remove the duplicate rows in the result set. The DISTINCT clause is an optional clause of the SELECT statement. Which hashid value do you use then?Īlso, Access uses something called 'AutoNumber' field as PK for a table, Oracle and SQL Server uses sequences to increment PK value in the tables. I tried commands 'INSERT OR REPLACE INTO' or 'INSERT OR IGNORE INTO' and both commands add duplicates at every run, unless I have set table1, key: timestamp as UNIQUE. Introduction to SQLite SELECT DISTINCT clause. Your 'pseudocode' logic may theoretically work if you always insert a record into the emailprops table related to the last record in email table, but is that always the case? You may have 100 records in email table, and you want to insert a record into emailprops table related to the 27th record in email table. ![]() But how do you know which record in emailprops table relates to which record in email table before you insert the record into emailprops table? And which hashid value to use as the value for compid in emailprops table? I don't think you can have this logic in the definition of the tables, you need to have it in the code that deals with INSERT INTO emailprops statements. So in order to INSERT any record into emailprops table, you need to have a record in the email table. Well, you have here Parent (email) - Child (emailprops) relationship between the 2 tables. ![]()
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