How to CAST a value in PostgreSQL for use in WHERE with LIKE statement? - postgresql

Question

I'm trying to fix a SQL query for later convert it to Doctrine2 DQL since it's part of a Symfony2 project. This is what my DDL has:
CREATE TABLE "nomencladores"."norma" (
"id" int4 NOT NULL,
"comite_tecnico_id" int4,
"numero" VARCHAR (10) COLLATE "default" NOT NULL,
"anno" int4 NOT NULL,
"nombre" VARCHAR (255) COLLATE "default" NOT NULL,
"activo" bool,
CONSTRAINT "norma_pkey" PRIMARY KEY ("id"),
CONSTRAINT "fk_f00cbe8e84edad75" FOREIGN KEY ("comite_tecnico_id") REFERENCES "nomencladores"."comite_tecnico" ("id") ON DELETE NO ACTION ON UPDATE NO ACTION
) WITH (OIDS = FALSE);
And I'm trying to execute a LIKE query to find %45% and I've tried all this queries without success:
The one generated by Doctrine2 in DQL
SELECT
n0_.numero AS numero0,
n0_.anno AS anno1,
n0_. ID AS id2,
n0_.nombre AS nombre3,
n0_.activo AS activo4,
n0_.comite_tecnico_id AS comite_tecnico_id5
FROM
nomencladores.norma n0_
WHERE
n0_.anno LIKE %45%;
Trying to cast the values
SELECT
n0_.numero AS numero0,
n0_.anno AS anno1,
n0_. ID AS id2,
n0_.nombre AS nombre3,
n0_.activo AS activo4,
n0_.comite_tecnico_id AS comite_tecnico_id5
FROM
nomencladores.norma n0_
WHERE
CAST (n0_.anno AS CHAR) LIKE %45%;
SELECT
n0_.numero AS numero0,
n0_.anno AS anno1,
n0_. ID AS id2,
n0_.nombre AS nombre3,
n0_.activo AS activo4,
n0_.comite_tecnico_id AS comite_tecnico_id5
FROM
nomencladores.norma n0_
WHERE
CAST (n0_.anno, "FM9999") LIKE %45%
SELECT
n0_.numero AS numero0,
n0_.anno AS anno1,
n0_. ID AS id2,
n0_.nombre AS nombre3,
n0_.activo AS activo4,
n0_.comite_tecnico_id AS comite_tecnico_id5
FROM
nomencladores.norma n0_
WHERE
to_char(n0_.anno, "FM9999") LIKE %45%
SELECT
n0_.numero AS numero0,
n0_.anno AS anno1,
n0_. ID AS id2,
n0_.nombre AS nombre3,
n0_.activo AS activo4,
n0_.comite_tecnico_id AS comite_tecnico_id5
FROM
nomencladores.norma n0_
WHERE
n0_.anno::text LIKE "%45%"
And none works, what is the right way to achieve this on PostgreSQL?

Answer 1

The syntax could be:
WHERE n0_.anno::text LIKE '%45%';
You need to cast the number to text (or varchar) before you can use it with the LIKE operator.
The right hand argument for LIKE is a text value. Your input is a string literal to be precise. You need single quotes for values, double quotes are for identifiers.
If anno is supposed to hold a year and you are just interested in the last two digits, make that:
WHERE n0_.anno::text LIKE '%45';
Or better, yet:
WHERE n0_.anno % 100 = 45;
% being the modulo operator. (Not related to the % symbol in LIKE patterns!)
45 (without quotes) being a numeric constant.