Oracle concat null

What is the string concatenation operator. Concatenate with NULL values in SQL. Use this function in applications that will be moved between environments with differing character sets.

But if ADDis null the output is ADDADD,ADD4. How to modify the query so that there is only one comma between ADDand ADD4. Description of the illustration concat. Both charand charcan be any of the datatypes CHAR, VARCHAR NCHAR, NVARCHAR CLOB, or NCLOB. The string returned is in the same character set as char1.

CONCAT returns charconcatenated with char2. Its datatype depends on the datatypes of the arguments. String-valued functions return NULL if the length of the result would be greater than the value of the max_allowed_packet system variable. Tuning Server Parameters”. For functions that operate on string positions, the first position is numbered 1. If you use any other condition with nulls and the result depends on the value of the null , then the result is UNKNOWN.

Because null represents a lack of data, a null cannot be equal or unequal to any value or to another null. I want to select a concatenation of a couple of fields, but with a separator between them. The separator should only be there if both operands are not null.

Please refer to DECODE for syntax and additional information. Up to you if you want to use deprecated features but they will cease to work in future versions and this connection option is not compatible with some SQL Server functionality. COALESCE returns the first non- null expr in the expression list. You must specify at least two expressions. If all occurrences of expr evaluate to null , then the function returns null.

Are there any interesting features I should be careful of? Ask Question Asked years, month ago. Oracle Database uses short-circuit evaluation. Active year, months ago. Viewed 493k times 91.

The data type of the result string depends on the data types of the two arguments. It’s part of standard string manipulation in many programming languages. The following example uses a concat _all function by James Padfiel which is a modification of a stragg function by Tom Kyte. The AskTOM team is taking a break over the holiday season. You can still search the repository of over 20questions answered.

Thanks for being a member of the AskTOM community. Check out our holiday messa. Trying it from TOAD the records that have NULL m. Removing it from the order by clause returns the three records with the NULL m. Any more suggestions please.