767 bytes in MySQL version 5.6 (and prior versions), is the stated prefix limitation for InnoDB tables. It’s 1,000 bytes long for MyISAM tables. This limit has been increased to 3072 bytes In MySQL version 5.7 (and upwards). You also have to be aware that if you set an index on a big char or varchar field which is utf8mb4 encoded, you have to … Read more
Just to clear up… or sum up… nchar and nvarchar can store Unicode characters. char and varchar cannot store Unicode characters. char and nchar are fixed-length which will reserve storage space for number of characters you specify even if you don’t use up all that space. varchar and nvarchar are variable-length which will only use up spaces for the characters you store. It will not reserve storage like char or nchar. nchar and nvarchar will take up twice as much storage space, so … Read more
TL;DR TEXT fixed max size of 65535 characters (you cannot limit the max size) takes 2 + c bytes of disk space, where c is the length of the stored string. cannot be (fully) part of an index. One would need to specify a prefix length. VARCHAR(M) variable max size of M characters M needs to be between 1 and 65535 takes … Read more
SQL Server 2012 and Later Just use Try_Convert instead: TRY_CONVERT takes the value passed to it and tries to convert it to the specified data_type. If the cast succeeds, TRY_CONVERT returns the value as the specified data_type; if an error occurs, null is returned. However if you request a conversion that is explicitly not permitted, then TRY_CONVERT … Read more
You need to apply a format during the cast, either Teradata style: or Oracle style: Btw, I added DATE in front of the string, it’s the recommended (and always reliable) way to write a date literal.
An nvarchar column can store any Unicode data. A varchar column is restricted to an 8-bit codepage. Some people think that varchar should be used because it takes up less space. I believe this is not the correct answer. Codepage incompatabilities are a pain, and Unicode is the cure for codepage problems. With cheap disk … Read more