我的乐与怒

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MySQL和MSSQL 查询比较

Current Date and Time MS: SELECT GETDATE() MY: SELECT NOW() Optionally: Use CURDATE() for the date only.Limiting Results MS: SELECT TOP 10 * FROM table WHERE id = 1 MY: SELECT * FROM table WHERE id = 1 LIMIT 10Date Field Default Value MS: DATETIME DEFAULT GETDATE() MY: DATETIME fields cannot have a default value, i.e. “GETDATE()” You must use your INSERT statement to specify CURDATE() for the field. Optionally: Use datatype TIMESTAMP DEFAULT CURRENT_TIMESTAMPCharacter Length MS: LEN() MY: CHARACTER_LENGTH() Aliases: CHAR_LENGTH(), LENGTH()Character Replace MS: REPLACE() works case insensitively MY: REPLACE() works case sensitivelyTrim Functions MS: LTRIM() and RTRIM() MY: TRIM()String Concatenation MS: CONCATENATION USING + (Does not automatically cast operands to compatible types) MY: CONCAT(string, string), which accepts two or more arguments. (Automatically casts values into types which can be concatenated)Auto Increment Field Definition MS: tablename_id INT IDENTITY PRIMARY