如何在Java中的db表中插入NULL值？

Question

The problem is that I can't figure out how to insert a null value. The column is date and if it's empty it just adds the current date to the db by default, but I don't know how to leave it empty or null if the user doesn't specify a custom date.

statement.executeUpdate("insert into table values(null, 100, 'text')");

This is the query. I've tried to skip the first value, insert a null, insert empty string, a 0 value. nothing seems to do the trick.

Answer 1

try the below code

String sql = "INSERT INTO temp(val) VALUES (?)";
PreparedStatement st = con.prepareStatement(sql);
if (/* int value is not null */) {
   st.setInt(1, value);
} else {
   set.setNull(1, Types.INTEGER);
}
count  = st.executeUpdate();

Answer 2

Use this form, where you specify what columns you intend to set:

INSERT INTO table_name (column1,column2,column3,...) 
VALUES (value1,value2,value3,...);

In your case:

insert into table (col2, col3) values (100, 'text')

(where of course col2 and col3 is the column names of your table)

Edit: The date column (col1) will probably need the constraint "Default null" for this to work as you intended.

Answer 3

in your column_date uncheck NOT NULL then you can insert NULL VALUES

simple code "INSERT INTO table_name ( field_name ) VALUES (NULL)