Got it, let's break down how to convert your Oracle TO_CHAR() call to work in MySQL. The exact approach depends on the data type of cus_inf.column1, since Oracle's TO_CHAR() handles numbers, dates, and other types differently. Here's what you need to know:

1. If column1 is a numeric type (INT, NUMBER, etc.) #

In Oracle, TO_CHAR(numeric_column) converts the number to a plain string without formatting. In MySQL, you can use either CAST() or CONVERT() to achieve the same result:

Option 1: Using CAST() #

SELECT CAST(cus_inf.column1 AS CHAR) AS no_operation
FROM cus_inf;

Option 2: Using CONVERT() #

SELECT CONVERT(cus_inf.column1, CHAR) AS no_operation
FROM cus_inf;

Both will turn your numeric value into a plain string, just like Oracle's unformatted TO_CHAR().

2. If column1 is a date/time type (DATE, TIMESTAMP, etc.) #

Oracle's TO_CHAR(date_column) uses a default format (usually something like DD-MON-RR). MySQL doesn't have an exact default match, so you'll need to use DATE_FORMAT() to replicate Oracle's default, or CAST() if you just want a standard string representation of the date.

Replicate Oracle's default date format #

If you need the same DD-MON-RR style (e.g., 05-JAN-24), use DATE_FORMAT() with the corresponding format specifiers:

SELECT DATE_FORMAT(cus_inf.column1, '%d-%b-%y') AS no_operation
FROM cus_inf;

Get a standard string date (MySQL's default) #

If you don't need to match Oracle's specific format and just want a readable string (like 2024-01-05 14:30:00), CAST() works perfectly:

SELECT CAST(cus_inf.column1 AS CHAR) AS no_operation
FROM cus_inf;

3. If column1 is already a string type #

If column1 is already a VARCHAR/CHAR in Oracle, the TO_CHAR() call is redundant. In MySQL, you can just select the column directly:

SELECT cus_inf.column1 AS no_operation
FROM cus_inf;

内容的提问来源于stack exchange，提问作者a.decales