问题
I'm trying to find all the data in ColumnX where the Data begins with a \.
Is like '\%' what I'm looking for? But the \ has to be at the beginning.
回答1:
Your syntax would work in standard SQL, because \ is not a meta character in strings. But it very much depends on which DBMS and version you are actually using - and what your current settings are.
In PostgreSQL POSIX-style escapes in strings used to be interpreted, so you would have to double \ to \\ to get an ordinary backslash.
The SQL standard says otherwise. So the PostgreSQL people have been preparing to switch over to standard behavior for years, introduced the special escape-string-syntax E'' and
a config setting escape_string_warning to make people aware of ambiguous syntax.
With version 9.1 they finally switched to "standard-conforming" strings. Now, if the global user configuration uses standard_conforming_strings = on, you can simply write:
... col like '\%'
Else you have to write:
... col like E'\\%'
Also, be aware that \ has special meaning in many client programs and programming languages. If strings get interpreted before they even reach the database engine, you may have to double the \ another time. See this related question, for instance.
回答2:
Indeed '\%' is what you need. The following statement brings all the data where columnX starts with '\'.
select * from table_name where columnX like '\%'
回答3:
this is what you need
回答4:
try this...
select * from myTable where ColumnX like '\%'
Good Luck!!!
来源：https://stackoverflow.com/questions/9141521/sql-select-where-column-begins-with