Code language: SQL (Structured Query Language) ( sql ) Add a NOT NULL constraint to a nullable column SQL Server issued the following error: String or binary data would be truncated. If the conversion fails, SQL Server terminates the statement and issues an error message.įor example, if you decrease the size of column c to 5 characters: ALTER TABLE t2 ALTER COLUMN c VARCHAR ( 5) Code language: SQL (Structured Query Language) ( sql ) However, when you decrease the size of the column, SQL Server checks the existing data to see if it can convert data based on the new size. You can increase the size of the column as follows: ALTER TABLE t2 ALTER COLUMN c VARCHAR ( 50) Let’s insert some sample data into the t2 table: INSERT INTO t2 The following statement creates a new table with one column whose data type is VARCHAR(10): CREATE TABLE t2 (c VARCHAR( 10))
Code language: SQL (Structured Query Language) ( sql ) Change the size of a column SQL Server issued the following error: Conversion failed when converting the varchar value to data type int. VALUES ( language: SQL (Structured Query Language) ( sql )įourth, modify the data type of the column from VARCHAR back to INT: ALTER TABLE t1 ALTER COLUMN c INT Third, insert a new row with a character string data: INSERT INTO t1 Second, modify the data type of the column from INT to VARCHAR: ALTER TABLE t1 ALTER COLUMN c VARCHAR ( 2) Second, insert some rows into the table: INSERT INTO t1 The new data type must be compatible with the old one, otherwise, you will get a conversion error in case the column has data and it fails to convert.įirst, create a new table with one column whose data type is INT: CREATE TABLE t1 (c INT)
To modify the data type of a column, you use the following statement: ALTER TABLE table_nameĪLTER COLUMN column_name new_data_type( size) Ĭode language: SQL (Structured Query Language) ( sql )
SQL Server allows you to perform the following changes to an existing column of a table:
#Error converting data type varchar to numeric. how to
Summary: in this tutorial, you will learn how to use the SQL Server ALTER TABLE ALTER COLUMN statement to modify a column of a table.
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