SQL Type Cast & CONVERT Generator
Quickly generate bulletproof T-SQL, PostgreSQL, MySQL, Oracle, and SQLite type casting statements. Convert string representations, decimals, floats, and timestamps into strict integer types with safe error fallback handlers.
Cross-Dialect SQL Cast Cheat Sheet
Direct syntax reference for casting data types to INTEGER across major relational engines:
| Database | Standard CAST | Safe Nullable Cast | Shorthand / Alternate |
|---|---|---|---|
| SQL Server (T-SQL) | CAST(col AS INT) |
TRY_CAST(col AS INT) |
CONVERT(INT, col) / TRY_CONVERT(INT, col) |
| PostgreSQL | CAST(col AS INTEGER) |
NULLIF(REGEXP_REPLACE(col, '[^0-9]', '', 'g'), '')::INT |
col::INTEGER or col::BIGINT |
| MySQL / MariaDB | CAST(col AS SIGNED) |
IF(col REGEXP '^[0-9]+$', CAST(col AS SIGNED), NULL) |
CONVERT(col, SIGNED) |
| Oracle PL/SQL | CAST(col AS NUMBER) |
TO_NUMBER(col DEFAULT NULL ON CONVERSION ERROR) |
TO_NUMBER(col) |
| SQLite | CAST(col AS INTEGER) |
CASE WHEN typeof(col) = 'integer' THEN col ELSE NULL END |
col + 0 (Implicit coercion) |
Deep Dive: Casting String Values to Integer in SQL Server
In relational database systems like Microsoft SQL Server (T-SQL), converting text data (such as VARCHAR or NVARCHAR) into a numeric integer is one of the most common ETL operations. Whether cleaning user input from web forms, parsing legacy import files, or performing mathematical aggregations on numeric codes, selecting the right casting function is critical for query stability and query optimizer performance.
1. The Difference Between CAST and CONVERT in T-SQL
SQL Server provides two native conversion functions:
CAST(expression AS target_type): Standard ANSI SQL. It is portable across various DBMS platforms including PostgreSQL, MySQL, and Oracle.CONVERT(target_type, expression [, style]): Proprietary to SQL Server. While redundant for simple integer casts, it provides an optionalstyleinteger parameter essential for formatting date and monetary conversions.
2. Why TRY_CAST is Crucial for Production Pipelines
Traditional CAST('abc' AS INT) aborts the entire transaction with the dreaded Msg 245, Level 16, State 1: Conversion failed when converting the varchar value 'abc' to data type int.
Introduced in SQL Server 2012, TRY_CAST and TRY_CONVERT inspect each record safely. If the string contains non-numeric characters, leading symbols, or exceeds the integer boundary (-2,147,483,648 to 2,147,483,647), it automatically evaluates to NULL rather than failing the transaction.
3. Handling Decimal Truncation vs Rounding
When casting a float or decimal like 84.95 to an integer, SQL Server truncates the fractional digits, yielding 84. If business logic requires standard arithmetic rounding (where 84.95 becomes 85), you must wrap the column in ROUND(col, 0) before executing the cast:
SELECT
TRY_CAST(ROUND(discount_rate, 0) AS INT) AS rounded_int
FROM sales_records;
Frequently Asked Questions
CAST(column_name AS INT) or CONVERT(INT, column_name). For safe conversions that return NULL instead of throwing conversion errors on non-numeric strings, use TRY_CAST(column_name AS INT) or TRY_CONVERT(INT, column_name).
CAST conforms to the ANSI SQL standard and throws a fatal execution error (e.g. Conversion failed when converting the varchar value to data type int) if the value cannot be parsed. TRY_CAST safely catches conversion failures and returns NULL without aborting query execution.
CAST(col AS integer) and the shorthand double-colon operator col::integer. MySQL uses CAST(col AS SIGNED) or CAST(col AS UNSIGNED) for whole numbers because MySQL dialect does not recognize CAST(... AS INT) directly.
CAST(ROUND(col, 0) AS INT) or FLOOR()/CEILING() depending on whether you require nearest, lower, or higher integer boundaries.